The temperature of 15.71 grams of gold rises from 32°C to 1,064°C, and then the gold melts completely. If gold’s specific heat is 0.1291 joules/gram degree Celsius and its heat of fusion is 63.5 joules/gram, how much energy is gained by the gold?

Answers

Answer 1
Hello!

The answer is:

The total energy gained is equal to 3091 Joules.

Why?

To calculate how much energy is gained by the gold, we need to use the formula to calculate the heat transfer, it's defined by the following equation:

[tex]Q=mc\Delta T[/tex]

We know that the gold melts completely (it reached its melting point or fusion temperature), so, we need to rewrite the equation as follow:

[tex]Q=mc\Delta T+m\Delta H_{fusion}[/tex]

Where,

m,is the mass of the material

c, is the specific heat of the material

ΔT, is the change of temperature.

ΔH, is the heat of fusion of the material.

So, from the statement we know the following information:

[tex]m=15.74grams\\\\\Delta T=1064\°C-32\°C=1032\°C\\\\c=0.1291\frac{Joules}{gram\°C}\\\\m\Delta H_{fusion=15.71grams*\frac{63.5Joules}{gram}=997.59Joules[/tex]

Then, substituting and calculating, we have:

[tex]Q=mc\Delta T+m\Delta H_{fusion}[/tex]

[tex]Q=15.71grams*0.1291\frac{Joules}{gram\°C}*1032\°C+997.59Joules[/tex]

[tex]Q=2093.06Joules+997.59Joules=3090.65Joules=3091Joules[/tex]

Hence, we have that the total energy gained is equal to 3091 Joules.

Have a nice day!


Related Questions

What is the pH of a solution that has a hydroxide ion concentration of 1.0×10−9 M?

Answers

Answer:

[tex]\boxed{\text{pH = 5.00}}[/tex]

Explanation:

Step 1. Calculate the pOH

pOH =-log[OH⁻]

pOH =-log(1.0 × 10⁻⁹)

pOH = 9.00

Step 2. Calculate the pH

pH + pOH = 14.00

pH + 9.00 = 14.00

[tex]\boxed{\textbf{pH = 5.00}}[/tex]

Final answer:

The pH of a solution with a hydroxide ion concentration of 1.0 × 10⁻⁹ M is 5, indicating the solution is acidic.

Explanation:

To calculate the pH of a solution with a known hydroxide ion concentration, we can use the relationship between the concentration of hydroxide ions ([OH-]) and hydrogen ions ([H+]), which is given by the ionic product of water (Kw = 1.0 × 10⁻¹⁴ at 25°C). The pH is defined as the negative logarithm of the hydrogen ion concentration, pH = -log([H+]).

Since we have the hydroxide ion concentration ([OH-] = 1.0 × 10⁻⁹ M) we can find the hydrogen ion concentration from Kw:

Kw = [H+] × [OH-]

[H+] = Kw / [OH-]

[H+] = (1.0 × 10⁻¹⁴ M2) / (1.0 × 10⁻⁹ M)

[H+] = 1.0 × 10-5 M

Now we can calculate the pH:

pH = -log([H+])

pH = -log(1.0 × 10⁻⁵)

pH = 5

A pH of 5 indicates that the solution is acidic, as a pH less than 7 is characteristic of an acidic solution.

Correct name for #10 please

Answers

Answer:

CH₃CH(CH₃)CH(C₃H₇)CH₂CH(CH₃)₂:

4-isopropyl-2-methylpentane.

Explanation:

Step One: Draw the structure formula of this compound. Parentheses in the formula indicate substitute groups that are connected to the carbon atom to the left.

For example, the first (CH₃) indicates that the second carbon atom from the left is connected to:

the CH₃- on the left-hand side,the -CH(C₃H₇)CH₂CH(CH₃)₂ on the right-hand side,a hydrogen atom, andan additional CH₃- group that replaced one hydrogen atom.

Each carbon atom in this compound is connected to four other atoms. All bonds between carbon atoms are single bonds.

The C₃H₇ in the second pair of parentheses is the condensed form of CH₃CH₂CH₂-. See the first sketch attached. Groups in parentheses are highlighted.

Step Two: Find the carbon backbone. The backbone of a hydrocarbon is the longest chain of carbon atoms that runs through the compound. See the second sketch attached. The backbone of this compound consists of seven carbon atoms and is highlighted in green. The name for this backbone shall be heptane.

Step Three: Identify and name the substitute groups.

The two substitute groups are circled in blue in the second sketch.

The one on the right -CH₃ is a methyl group.The one on the left is branched. [tex]\begin{aligned}\text{CH}_3-&\text{CH}-\text{CH}_3\\[-0.5em]&\;|\end{aligned}[/tex] This group can be formed by removing one hydrogen from the central carbon atom in propane. The name for this group is isopropyl.

Step Four: Number the atoms.

Isopropyl shall be placed before methyl. Start from the right end to minimize the index number on all substitute groups. The methyl group is on carbon number two and the isopropyl group on carbon number four. Hence the name:

4-isopropyl-2-methylheptane.

Acid rain is represented by the formula H2SO4. How many atoms of sulfur are present in one molecule of acid rain?

One

Two

Four

Six

Answers

Answer: A. one atom

Explanation: i did some research on it and that is what i found.

One molecule of H₂SO₄ comprises one atom of sulfur. Thus, option A is correct.

What is acid rain?

Acid rain is given as the precipitation that has been comprising the chemical compound acidic in nature, thereby the pH of the precipitation as well.

The number of atoms in a molecule can be determined with the chemical formula. The subscript to an element in the formula is corresponding to the number of atoms of element present in the molecule or atom.

In the molecule of H₂SO₄,  the subscript number to the hydrogen atom is 2, thereby 2 hydrogens are present, and the subscript to the sulfur is the representation of the number of atoms of sulfur in the molecule that stands for 1.  

Therefore, 1 atom of sulfur is present in the molecule of H₂SO₄. Thus, option A is correct.

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the movement of water from ocean through the atmosphere and back

Answers

Answer:

Water cycle

Explanation:

The water from the ocean and sea evaporates into the atmosphere and goes into the sky to form clouds.

This turns the liquid water into water vapor in the atmosphere. Plants, too, help water get into the atmosphere through a process called transpiration! After absorbing water from the ground, plants “sweat” water vapor through their leaves to stay cool. Water can also get into the atmosphere from snow and ice.

Which statement correctly describes measuring with a graduated cylinder?​

Answers

Answer:

what are the options because a graduated cylinder is a science mixing cylinder is a common piece of laboratory equipment used to measure the volume of a liquid

Explanation:

Is freshly squeezed grapefruit juice a homogeneous or heterogeneous mixture?

Answers

Answer:

Homogeneous because if you were to take a sip it would be the same all throughout the juice, nothing changes. Hope this helped, please mark me the brainliest answer? Have a good day :)

Answer:

Explanation:

heterogeneous

all my best girl freinds are offline there not my gf there my best freind i just be pulling a lot of girls

now can u help me with this question Utah is close to an ocean, while New York City is landlocked.
B.
New York City is close to an ocean, while Utah is landlocked.
C.
New York City lies in a rain shadow area.
D.
New York City is closer to mountains.

Answers

New York City is close to an ocean and to the great lakes.

Utah is one of the landlocked states.

B. New York City is close to an ocean, while Utah is landlocked.

Thanks

The answer is B. New York City is close to an ocean while Utah is landlocked (landlocked means that it has land on all sides)

If you are confused look at the map below (First pic is Utah and second one is NYC)

Hope this helped!

~Just a girl in love with Shawn Mendes

About how far is it from red bank to Belleville?
Answers:
A) 1 km
B) 10 km
C) 20 km
D) 30 km

Answers

Answer:

It would be 30km

Explanation:

Final answer:

The approximate straight-line distance between Red Bank and Belleville, presumably in New Jersey, USA, is about 30 kilometers, making 'option D: 30 km' the correct choice from the given options.

Explanation:

The distance between Red Bank and Belleville can vary based on the specific locations in each place, the method of travel, and the route that is chosen. However, to determine the approximate distance between these two locations, one might use a mapping service or tool. Assuming these are the towns in New Jersey, USA, and using a direct path (as the crow flies), the distance is about 30 kilometers. Therefore, out of the options provided, the answer would be option D: 30 km. Note that real-world road distances might be different because roads do not always make straight, direct paths between locations.

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how many molecules are in 3.6 grams of NaCl?

Answers

Final answer:

To find the number of molecules in 3.6 grams of NaCl, convert the grams to moles of NaCl using its molar mass and then multiply the number of moles by Avogadro's number (6.02 x 10^23). The result is approximately 3.7 x 10^22 molecules.

Explanation:

To find out how many molecules are in 3.6 grams of NaCl, first calculate the number of moles of NaCl. Each mole of NaCl has a mass of 58.44 grams (sum of atomic masses of Na and Cl). So, 3.6 grams corresponds to 3.6/58.44 = 0.0616 moles.

Now, use the Avogadro's number which states that one mole of any substance contains 6.02 x 10^23 molecules. So, 0.0616 moles of NaCl would contain approximately 0.0616 x 6.02 x 10^23 = 3.7 x 10^22 molecules.

In conclusion, the number of molecules in 3.6 grams of NaCl is approximately 3.7 x 10^22.

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To find the number of molecules in 3.6 grams of NaCl, first calculate the number of moles (0.0615 moles), then convert this to molecules using Avogadro's number, resulting in approximately 3.70 x 10²² molecules.

To determine the number of molecules in 3.6 grams of NaCl, follow these steps:

Calculate the molar mass of NaCl: The molar mass of NaCl is the sum of the atomic masses of sodium (Na) and chlorine (Cl). Thus, the molar mass of NaCl is 23.0 g/mol (Na) + 35.5 g/mol (Cl) = 58.5 g/mol.Find the number of moles in 3.6 grams of NaCl: Use the formula: number of moles = given mass / molar mass.

              Number of moles of NaCl = 3.6 g / 58.5 g/mol ≈ 0.0615 moles

Convert moles to molecules: Use Avogadro's number, which is 6.022 x 10²³ molecules per mole.

         Number of molecules = 0.0615 moles x 6.022 x 10²² molecules/mole ≈ 3.70 x 10²² molecules

Therefore, there are approximately 3.70 x 10²² molecules in 3.6 grams of NaCl.

What are some characteristics of a conductor of metal. Give at least 4 examples

Answers

Explanation:

Metals are the substances or elements that contain more number of electrons.

Some of the properties of metals are as follows.

Metals are good conductors of heat and electricity.They have shiny surface, that is, they are lustrous.Metals are malleable that is, they can be drawn into thin sheets.Metals are also ductile in nature that is, they can be drawn into thin wires.

The density of glycerin is 1.26 Grams/cm^3. How many lbs/ ft is this? Use the conversion rates of 454g/1 lbs and 28317 cm^3/ 1 ft^3 . Express your answer to the correct number of significant figures. The density is .

Answers

Hello!

The answer is:

The density is equal to:

[tex]78.6\frac{lb}{ft^{3} }[/tex]

Why?

This a unit conversion problem, so, converting  the density  of glycerin from [tex]gram/cm^{3}[/tex] to [tex]\frac{lb}{ft^{3}}[/tex]  using the given conversion rates, we have:

[tex]1.26\frac{gram}{cm^{3}}*\frac{1lb}{454gram}*\frac{28317cm^{3} }{1ft^{3} }=78.59\frac{lb}{ft^{3} }[/tex]

Rounding to three significant figures, we have that the density is equal to:

[tex]78.6\frac{lb}{ft^{3} }[/tex]

Have a nice day!

78.6

The density is 78.6

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Can someone help me a will really appreciated. I need help fast i need someone to answer all the questions. You get 10 points

Answers

Answer:

1. Theory

2. evidence

3. theory

4. Today, natural sciences are more commonly divided into life sciences, such as botany and zoology; and physical sciences, which include physics, chemistry, geology, astronomy, and materials science.

5.In everyday language a theory means a hunch or speculation. Not so in science. In science, the word theory refers to a comprehensive explanation of an important feature of nature supported by facts gathered over time. Theories also allow scientists to make predictions about as yet unobserved phenomena".

7.Empirical evidence is information acquired by observation or experimentation. Scientists record and analyze this data. The process is a central part of the scientific method

8. Field research is a research conducted in the real world or a natural setting. It tends to observe, analyze, and describe what exists rather than manipulating a factor under study .On the other hand, controlled laboratory research is a research conducted in a setting specifically designed for research

10.You would say Scientific knowledge is always being changed and performed in different ways. Scientific knowledge is always being changed as scientist are experiencing and collecting new information everyday using the scientific method.

6.In general, a scientific law is the description of an observed phenomenon. It doesn't explain why the phenomenon exists or what causes it. The explanation of a phenomenon is called a scientific theory. It is a misconception that theories turn into laws with enough research.

The salt formed from the Acid/ Base reaction between HBr and NaOH is called

Answers

HBr + NaOH --> NaBr + H2O

The salt in this equation is NaBr, Sodium Bromide. Salts are identified as a non-metal, Bromide, and a metal, Soduim.

The salt formed from the reaction between HBr and NaOH is sodium bromide (NaBr), which is the result of a neutralization reaction involving the combination of hydroxide ions from the base with hydrogen ions from the acid, and the combination of sodium ions from the base with bromide ions from the acid.

The salt formed from the acid/base reaction between HBr (hydrobromic acid) and NaOH (sodium hydroxide) is called sodium bromide (NaBr). When these two reactants combine in a neutralization reaction, the hydroxide ions (OH⁻) from the base react with the hydrogen ions (H⁺) from the acid to produce water (H₂O), and the remaining sodium ions (Na⁺) from the base combine with the bromide ions (Br⁻) from the acid to form the salt sodium bromide (NaBr).

This can be represented by the chemical equation:

NaOH (aq) + HBr (aq) rightarrow NaBr (aq) + H2O (l)

A salt is generally an ionic compound made up of the cation from a base and the anion from an acid. As HBr is a strong acid and NaOH is a strong base, the resulting sodium bromide solution has a neutral pH, similar to sodium chloride (NaCl).

what is the molar mass of Mg(NO3)2

Answers

Answer: The molar mass of magnesium nitrate is 148.3148 g/mol.

Explanation:

The molar mass of [tex]Mg(NO_3)_2[/tex] is approximately 148.33 grams/mole.

Calculating the total mass of one mole of the chemical [tex]Mg(NO_3)_2[/tex] (magnesium nitrate) is necessary to determine its molar mass. The molar mass is determined by adding the atomic masses of all the components of the compound, taking into account the value of each subscript.

The elements involved have the following atomic masses:

Magnesium (Mg) = 24.31 grams/mole

Nitrogen (N) = 14.01 grams/mole

Oxygen (O) = 16.00 grams/mole

Magnesium nitrate [tex](Mg(NO_3)_2)[/tex] consists of one magnesium atom (Mg), two nitrate ions [tex](NO^3^-)[/tex], and their respective subscripts.

This formula can be used to obtain the molar mass:

Molar mass of [tex]Mg(NO_3)_2[/tex]=  (1 × Mg) + (2 × (N + (3 × O)))

Molar mass of [tex]Mg(NO_3)_2[/tex]= (1 × 24.31) + (2 × (14.01 + (3 × 16.00)))

Molar mass of [tex]Mg(NO_3)_2[/tex]= 24.31 + (2 × (14.01 + 48.00))

Molar mass of [tex]Mg(NO_3)_2[/tex]=24.31 + (2 × 62.01)

Molar mass of [tex]Mg(NO_3)_2[/tex]=24.31 + 124.02

Molar mass of [tex]Mg(NO_3)_2[/tex]= 148.33 grams/mole

Therefore, the molar mass of [tex]Mg(NO_3)_2[/tex] is approximately 148.33 grams/mole.

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A contour line connects points of the same _____.
A. latitude
B. longitude
C. elevation
D. rock type

Answers

Answer:

the answer is elevation

Answer: C. Elevation

The Lewis dot notation for two atoms is shown.

Na is written with a dot on its right. Cl is written on the right of Na. There are seven dots around Cl. An arrow points from the dot near Na to Cl.

What is represented by this notation?

Answers

To help, I drew a diagram. This represents an ionic bond between Na and Cl. Na is giving his single electron to Cl, which is indicated by the arrow, to make Cl full with 8 electrons.

Explanation:

Atomic number of sodium is 11 and its electronic distribution is 2, 8, 1. So, it means there is only one valence electron present in a sodium atom. This valence electron is represented by a dot in the Lewis structure.

Atomic number of chlorine is 17 and its electronic distribution is 2, 8, 7. So, it means there are seven valence electrons present in a chlorine atom. These valence electrons are represented by seven dots in the Lewis structure.

Also, in order to attain stability sodium will lose one valence electron and this valence electron will be gained by chlorine atom.

Therefore, an arrow pointed from dot near Na to Cl shows that an electron is being donated from Na to the Cl atom.

12. The most common factors that cause chemical reactions to occur are all the following except
[A] transfer of electrons [B] formation of a solid
[C] formation of water
[D] formation of a gas
[E] a decrease in temperature

Answers

Final answer:

A decrease in temperature [E] is generally not a cause of chemical reactions. Other factors like the transfer of electrons, formation of a solid, water or gas are common causes.

Explanation:

The most common factors that can cause chemical reactions to occur include the transfer of electrons, formation of a solid, formation of water, and formation of a gas. However, the option that does not generally cause a chemical reaction to occur is a decrease in temperature [E]. In fact, an increase in temperature typically facilitates chemical reactions as it increases the energy of the particles involved, making them more likely to react.

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Final answer:

Most commonly, chemical reactions occur due to the transfer of electrons, the formation of a solid, the formation of water, or the formation of a gas. A decrease in temperature is not typically a factor that facilitates chemical reactions.

Explanation:

The most common factors that cause chemical reactions to occur include the transfer of electrons, the formation of a solid, the formation of water, and the formation of a gas. These actions involve breaking and forming chemical bonds that result in new substances. However, a decrease in temperature is typically not a factor that causes chemical reactions. In fact, an increase in temperature is more likely to cause a chemical reaction as it provides the necessary energy for the particles to react.

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A train is traveling at 50.0 miles per hour 1 mile is equal to 1.61
kilometers. How fast is the train moving in meters per second?
m/s​

Answers

Answer:

The train is moving at the speed of 22.36 meters per second

Explanation:

Speed of the train  = 50 .0 miles/hour

1 mile = 1.61 km

50 miles = [tex]50.0\times 1.61 km=80.5 km[/tex]

1 km = 1000 m

1 hour = 3600 seconds

So,the speed of the train in meter per seconds:

[tex]=\frac{80.5\times 1000 m}{3600 s}=22.36 m/s[/tex]

In an endothermic physical or chemical change,.

A)the potential energy of the system increases
B)all of these
C)the system absorbs heat from its surroundings
D)kinetic energy is converted into potential energy and seems to disappear

Answers

Answer:

c

Explanation:

If chemical equation neads heat to happen it's caled endothermic

eg. CaCO3 ---> CaO + CO2 (there is supposed to be a little t above the arrow)

Endothermic reactions are chemical reactions in which the reactants absorb heat energy from the surroundings to form products. Hence, option C is correct.

What is an endothermic reaction?

Endothermic reactions are chemical reactions in which the reactants absorb heat energy from the surroundings to form products

In an endothermic reaction, the products are higher in energy than the reactants.

Therefore, the change in enthalpy is positive, and heat is absorbed from the surroundings by the reaction.

Hence, option C is correct.

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67.4 L of sulfur dioxide (SO2) gas at 0.0C and at 1 atm of pressure is equivalent aren’t to how many moles?

Answers

Solution here,

Volume(V)=67.4 L

Pressure(P)=1 atm

Temperature(T)=(0+273)K=273K

Universal gas constant(R)=0.0821 L.atm.mol^-1K^-1

No. of moles(n)=?

Now,

PV=nRT

or, 1×67.4=n×0.0821×273

or, 67.4=22.4n

or, n=67.4/22.4

or, n=3

therefore, required no. of mole is 3.

what is the sweetened tea mixture called

Answers

Answer:

The sweetened tea mixture is called homogeneous.

The sweetened tea mixture is a homogeneous mixture unlike the heterogeneous mixture which has 2 phases.

What are heterogeneous mixture?

Heterogeneous mixtures is defined as a type of mixture where  the composition is not uniform throughout the mixture.It consists as two or more phases. The phases are chemically distinct  and separate from each other.

As there are two or more phases present in heterogeneous mixtures they can be separated by solvent extraction  method where in one phase is miscible with the solvent while the other phase is immiscible.

Components of a heterogeneous mixtures are distinctly visible . There are two types of heterogeneous mixtures, the colloids and the suspensions.These two differ with each other with respect to particle size.It consists of 2 or more phases.

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measles is a disease that causes fever and rash the graph gives the number of measles causes in the US between 1954 and 2008 the measles vaccine was introduced in 1960. What can you conclude using the info on a graph​

Answers

Final answer:

The introduction of the measles vaccine in the US in 1960 led to a significant decrease in the number of measles cases.

Explanation:

The information on the graph shows the number of measles cases in the US between 1954 and 2008. The graph shows that the measles vaccine was introduced in 1960. From the graph, we can conclude that the introduction of the measles vaccine led to a significant decrease in the number of measles cases in the US. Prior to the vaccine, there were fluctuating numbers of cases, but after the vaccine was introduced, the number of cases dropped to almost zero.

Which is an acid-conjugate base pair?

Answers

Final answer:

An acid-conjugate base pair is when an acid donates a proton to form a conjugate base, or when a base accepts a proton to form a conjugate acid. The strength of an acid is inversely related to the strength of its conjugate base, with strong acids having weak conjugate bases and vice versa.

Explanation:

An acid-conjugate base pair involves a unique relationship in chemical reactions, particularly in the Brønsted-Lowry acid-base theory. In this concept, an acid and a base differ by just one hydrogen ion (H+).

Essentially, if an acid donates an H+ ion, it forms its conjugate base, and if a base accepts an H+ ion, it becomes its conjugate acid.

An example of such a pair is hydrofluoric acid (HF) and fluoride ion (F−), where HF is the parent acid and F− is the conjugate base. Another example is the water molecule (H₂O) acting as a base to form the hydronium ion (H₃O+), its conjugate acid.

A general rule in acid-base chemistry is that the strength of an acid is inversely related to the strength of its conjugate base.

The relative strength of acid-conjugate base pairs is thus an important concept; strong acids have very weak conjugate bases, while strong bases form very weak conjugate acids upon acceptance of a proton.

This relationship helps predict the direction of acid-base reactions and the position of equilibrium.

Final answer:

An acid-conjugate base pair is derived from an acid losing a proton to become its conjugate base; for instance, CH₃CO₂H and CH₃CO₂⁻ make up such a pair. The strength of an acid is inversely related to its conjugate base.

Explanation:

An acid-conjugate base pair consists of two species that differ by the presence or absence of a proton (H+). According to the Brønsted-Lowry theory, an acid is a proton donor and a base is a proton acceptor. When an acid donates a proton, it becomes its conjugate base, and when a base accepts a proton, it becomes its conjugate acid. For example, when we take the acetic acid (CH₃CO₂H) and it donates a proton (H+), it forms the acetate ion (CH₃CO₂⁻), making CH₃CO₂H and CH₃CO₂⁻ a conjugate acid-base pair. Similarly, water (H₂O) can accept a proton to become hydronium (H₃O+), creating the conjugate acid-base pair H₂O and H₃O+.

The relative strength of an acid and its conjugate base is inversely related: the stronger the acid, the weaker the conjugate base, and vice versa. Therefore, the conjugate base of a strong acid like hydrochloric acid (HCl) is a weaker base (Cl⁻), and the conjugate acid of a strong base like hydroxide (OH⁻) is a weaker acid (H₂O).

Justin mixed two clear liquids together during an experiment and made the following observations:

The mixed liquids decreased in temperature without any refrigeration or other action to change the temperature.
The color of the liquid changed to blue.
Which statement best describes Justin’s experiment?

A.
A physical change occurred, and this caused the liquid’s chemical properties to change.
B.
A chemical change occurred, and this caused the liquid’s physical properties to change.
C.
A physical change occurred, so only physical properties changed.
D.
A chemical change occurred, so only chemical properties changed.

Answers

Answer:

B. A chemical change occurred which caused the liquid's physical properties to change.

Explanation:

The reduction of the temperature of the system meant that the reaction absorbed heat energy from it. This shows that a chemical reaction was in progress. New products were formed, and this is proved by the change in the color to blue.  

Answer: Option (B) is the correct answer.

Explanation:

A chemical reaction in which energy is absorbed by the reactant molecules is known as endothermic reaction. In this type of reaction there occurs decrease in temperature.

For example, Justin mixed two clear liquids together during an experiment and he noticed that decrease in temperature occurs without any refrigeration or other action to change the temperature.

Then it means an endothermic reaction has occurred.

Sometimes, chemical changes also leads to change in color of the reaction mixture.

Whereas a chemical reaction in which energy is released by the reactant molecules is known as exothermic reaction. In this type of reaction there occurs an increase in temperature.

A physical change is that change which does not lead to any difference in chemical properties of a substance.

For example, mass, density, etc are all physical properties.

On the other hand, a chemical reaction is that change which leads to change in chemical properties of a substance.

For example, combustion, toxicity, etc are all chemical properties.

Thus, we can conclude that the statement a chemical change occurred, and this caused the liquid’s physical properties to change, best describes Justin’s experiment.

6.5 moles of Al (aluminum) reacts with 7.2 moles of H2O (water). Which is the limiting reactant? Calculate the theoretical yield. Balance equation : 2Al + 3 H2O == Al2O3 + 3H2

Answers

Answer:

1. The limiting reactant is H₂O.

2. The theoretical yield of Al₂O₃ = 978.8 g.

Explanation:

1. Which is the limiting reactant?

The balanced equation for the mentioned reaction is:

2Al + 3H₂O → Al₂O₃ + 3H₂,

It is clear that 2.0 moles of Al react with 3.0 moles of H₂O to produce 1.0 moles of Al₂O₃ and 3.0 mole of H₂.

From stichiometry; Al reacts with H₂O with (2: 3) molar ratio.

4.8 mol of Al (the remaining 1.7 mol is in excess) reacts completely with 7.2 mol of H₂O with (2: 3) molar ratio.

So,

the limiting reactant is H₂O and the excess reactant is Al.

2. Calculate the theoretical yield.

To calculate the theoretical yield, we should get the no. of moles of produced Al₂O₃:

Using cross multiplication:

2.0 moles of Al produce → 1.0 moles of Al₂O₃.

4.8 moles of Al produce → ??? moles of Al₂O₃.

∴ The no. of moles of Al₂O₃ produced = (1.0 mol)(4.8 mol)/(2.0 mol) = 9.6 mol.

The theoretical yield of Al₂O₃ = (no. of moles)(molar mass) = (9.6 mol)(101.96 g/mol) = 978.8 g.

explain what happens in a nuclear chain reaction

Answers

Answer:

Nuclear Chain Reactions. A chain reaction refers to a process in which neutrons released in fission produce an additional fission in at least one further nucleus. This nucleus in turn produces neutrons, and the process repeats. The process may be controlled (nuclear power) or uncontrolled (nuclear weapons).

Explanation:

Final answer:

A nuclear chain reaction occurs when an initial reaction causes more reactions, generating recurring secondary reactions, forming a self-sustaining chain, much like a domino effect. This process is common in nuclear fission and fusion.

Explanation:

In a nuclear chain reaction, an initial reaction causes excess neutrons to be emitted. These neutrons then cause other similar nuclear reactions, generating more neutrons and thus, more nuclear reactions. This sequence forms a self-sustaining chain. This is common in both nuclear fission, as seen in nuclear power plants and atomic bombs, or in a controlled manner in nuclear fusion, as is being researched for future clean energy solutions. It's like a domino effect but with atomic nuclei and neutrons.

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How many grams are there in 5.0×1024 formula units of ammonia

Answers

Answer:

141.1g

Explanation:

The formula of ammonia is written as NH₃

Given parameters:

Number of particles = 5.0 x 10²⁴atoms

To calculate the mass of the substances that makes up this number of ammonia particles, we follow use the mole concept to derive it.

1. We know that a mole is the amount of a substance that contains the Avogadro's number of particles i.e 6.02 x 10²³

From this, we can then derive the number of moles using the expression below:

Number of moles =

number of particles/6.02 x 10²³

2. With the number of moles, we can deterime the mass using the expression below:

Number of moles= mass/molar mass

Mass(g) = number of moles x molar mass

Solution

From step 1:

Number of moles = 5.0 x 10²⁴ / 6.02 x 10²³

No of moles of NH₃ = 0.83 x 10 = 8.3mol

Step 2:

Molar mass of NH₃:

Atomic mass of N = 14gmol⁻¹

H = 1gmol⁻¹

Molar mass = 14 + (1x3) = 17gmol⁻¹

Using the expression:

Mass(g) = number of moles x molar mass

Mass of NH₃ = 8.3 x 17 = 141.1g

E. The element 231/90Th decays to 231/91 Pa. Use the laws of conservation of charge and nucleon number to determine the decay particle emitted. Explain your reasoning.

Answers

Answer:

A negatron emission

Explanation:

We know that radioactivity orginates from instability of the nucleus. When the nucleus is unstable, radioactive emissions are produced in the form of any of these rays:

> Alpha particle emisson

>Beta particles

> Gamma rays

These emissions create a balance for a radioactive decay.

In balancing nuclear reactions we make sure that the charges on both sides must be conserved and that the mass number and atomic numbers conserved too. This means that the sum of mass number and atomic numbers on both side of the reaction must be equal.

The nucleons are the protons and neutrons, they add up to give the mass number. The atomic number is the proton number.

For the given radioactive reaction:

²³¹₉₀Th → ²³¹₉₁Pa + ?

From this equation, we see that the mass number is conserved but the atomic number is not.

The mass number is the superscript whereas the atomic number is the subscript.

Let's say the decay produces an emission of a particle denoted by X

²³¹₉₀Th → ²³¹₉₁Pa + ᵃₙX

What would the nature of X be?

For the charges and masses to be conserved, X must have mass number of 0 and an atomic number of -1.

Checking:

Mass number:

231 = 231 + a ( a is the mass number)

a = 231 - 231 = 0

Atomic number:

90 = 91 + n

n = 90- 91 = - 1

With X having a mass number of 0 and an atomic number of -1, we have a beta particle emission. Specifically, a negatron has been emitted.

A negatron is denoted as ⁰₋₁β which perfectly makes the equation conserved and suits the description of X.

The complete equation is thus written as:

²³¹₉₀Th → ²³¹₉₁Pa + ⁰₋₁β + energy

In the decay of thorium-231 to protactinium-231, a neutron inside the thorium nucleus converts to a proton, resulting in the emission of a beta particle to conserve charge and nucleon number.

The decay of the element thorium-231 (231/90Th) to protactinium-231 (231/91Pa) involves the emission of a decay particle. According to the laws of conservation of charge and nucleon number, we can determine the type of decay and the particle emitted by examining the change in atomic and mass numbers.

231/90Th decays to 231/91Pa which indicates that the mass number has not changed (indicating the total number of protons and neutrons remains constant) but the atomic number has increased by one. This suggests that a neutron has transformed into a proton and the particle emitted must account for the negative charge to conserve the total charge. Since a neutron (n) converting to a proton (p) emits a beta-minus particle ({{e}}) (an electron), which has a negative charge, the decay particle is therefore identified as a beta particle.

Which best describes why governmental funding for scientific research is
important?
A. Governmental funding always determines what a scientist thinks
is right and wrong.
O
B. Governmental funding provides more money than private funding.
C. Governmental funding provides a way to control what kind of
scientific research is done.
D. Governmental funding guarantees that all scientific research will
help everyone

Answers

I think C is the perfect answer. This is because if the govermental funding do not provide a way to control the scientific research, then scientists might done their jobs illegally as they can do anything to complete their experiment and research.

Answer:

Explanation:

Specifically, scientific research can be defined as an activity developed by researchers, aiming at new discoveries and thus contributing to the quality of intellectual life. Still, the research includes some of the activities developed during academic life, which requires from the researcher some skills necessary for the full development of their functions, such as planning, knowledge and adaptation to scientific norms.

Scientific research is very important for the development of the country, and for a scientific research to be completed and to achieve good results, this research needs funding, to buy equipment and other elements necessary for the research to be carried out. It is very important for research to receive government funding, as government usually provides more funding than private companies, especially in research done in underdeveloped countries.

Which of the following is a non metal that remains liquid at room temperature?

A. Phosphorous
B. Bromine
C. Chlorine
D. Helium


Chlorophyll is a naturally occurring chelate compound in which central metal is

A. copper
B. magnesium
C. iron
D. calcium

Answers

Answer:

1st answer B. Bromine

2nd answer B. magnesium

Explanation:

Hello There!

Which of the following is a non metal that remains liquid at room temperature? "OPTION B"

Chlorophyll is a naturally occurring chelate compound in which central metal is "OPTION B"

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