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.
Which Type of thermal energy uses electromagnetic waves to transfer energy
Answer:
The correct answer is radiation thermal energy.
Explanation:
The transfer of energy in thermal energy comprises the transfer of internal energy. The three kinds of thermal energy transfer are convection, conduction, and radiation. In convection, the movement of warm particles takes place, in conduction the direct contact of atoms occurs, and in radiation, the transfer of energy takes place in the form of electromagnetic waves.
what is Newton's 1st Law of Motion
The law of inertia. Basically, every object stays in the same spot unless they are moved by an external force, .
An object at rest will remain at rest or an object in motion will remain in motion unless acted upon an unbalanced force
charles law states that if given quantity of gas is held at a constant pressure, then its volume is directly proportional to the abosolute temperature. this law explains what
Answer:
it explains the relationship between temperature and volume
Charles law states that if given quantity of gas is held at a constant pressure, then its volume is directly proportional to the absolute temperature. this law explains relation between temperature and volume.
What is Charles law?Charles' law is just a gas statement that governs how gases increase while heated in an experimental setting. The Kelvin temperature and volume should be in direct proportion whenever the pressure on such a test of dry gas was maintained constant, according to a modern version of Charles's law.
What is volume?
A scalar quantity that expresses the proportion of three-dimensional area contained by a sealed surface will be called volume.
Therefore, Charles law states that if given quantity of gas is held at a constant pressure, then its volume is directly proportional to the absolute temperature. this law explains relation between temperature and volume.
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Which of the following is not evidence for the law of conservation of mass during cellular respiration? A. The products from cellular respiration are created from the same elements (carbon, oxygen, and hydrogen) that make up the reactants. B. cellular respiration creates an energy molecule when glucose is broken down
Answer:
Cellular respiration creates an energy molecule when glucose is broken down. B.
What type of reaction is a neutralization reaction?
Which is a a characteristic of a strong acid ?
Answer:
It completely dissociates in water.
Explanation:
The characteristic of a strong acid is that it completely dissociates when dissolved in water to form ions.
What are acids?
Acids are defined as substances which on dissociation yield H+ ions , and these substances are sour in taste. Compounds such as HCl, H₂SO₄ and HNO₃ are acids as they yield H+ ions on dissociation.
According to the number of H+ ions which are generated on dissociation acids are classified as mono-protic , di-protic ,tri-protic and polyprotic acids depending on the number of protons which are liberated on dissociation.
Acids are widely used in industries for production of fertilizers, detergents batteries and dyes.They are used in chemical industries for production of chemical compounds like salts which are produced by neutralization reactions.
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Which of those is a balanced chemical equation? (super important)
I believe C is the balanced equation.
C is the answer i think
The potential energy diagram shows the gain and loss of potential energy as water molecules decompose into hydrogen and oxygen. Label the parts of the diagram.
products
reactants
activated
complex
activation
energy
enthalpy of
reaction
chemical potential energy
progress of reaction
Answer:
Kindly find the attached image.
Explanation:
Activation energy: is the difference in potential energy between the activated complex and reactants.
Enthalpy of reaction: is the difference in potential energy between the products and reactants.
Answer : The energy diagram is shown below.
Explanation :
Activated complex : When the reactant molecules absorb energy then their bonds are loosened and new lose bonds are formed between them.
The intermediate formed is known as activated complex and it is an unstable state and immediately dissociates to form the stable products.
Activation energy : It is defined as the minimum amount of energy absorbed by the reactant molecules so that their energy becomes equal to the threshold energy. Or we can say that, the difference between the reactant and the activated complex.
Enthalpy of reaction : It is defined as the energy change that takes place when the reactants go to the products. It is represented as, [tex]\Delta H[/tex]. Or we can say that, the difference between the product energy and the reactant energy.
Hence, the energy diagram is shown below.
What causes the Brownian motion of particles in a colloid?
a) collisions between the particles and surrounding molecules
b)interactions with rays of light that shine through the colloid
c )the force of gravity, which pulls the particles downward
d) electrical attractions between the particles and surrounding molecules
Answer:
The correct answer option is a) collisions between the particles and surrounding molecules.
Explanation:
The collisions between the particles and surrounding molecules causes the Brownian motion of particles in a colloid.
Brownian motion is the irregular movement of the microscopic particles in a fluid which bombard into each other.
It basically is the result of the molecules of a dispersion medium colliding with the dispersed particles of the phase.
How many grams of H2 are needed to produce 13.33g of NH3?
The reaction to form NH3 is : N2 + 3H2-> 2NH3 12,33g NH3 is 12,33/17,03=0,3 =0,724 moles of NH3 moles NH3. So you need 1,5*0,724 = 1,086 moles H2 1,086*2,016 = 2,189 g of H2 is needed ro form 12,33 g NH3
Which of the following might a biologist choose to study?
A. The pigments used in Claude Monet's paint
B. Wind patterns on Mars
C. The effects of ultraviolet light on red paint
D. The causes of honeybee deaths in beehives
Answer:
D
Explanation:
All the others are unrelated to biology as biology is the study of life (hence bio) and not chemistry or anything else.
A biologist might study the causes of honeybee deaths in beehives, as it falls within the biological study of organisms, their ecosystems, and their interaction with the environment. Ecologists, as biologists, may study predator-prey dynamics and the role of biodiversity and ecological succession in species survival.
Explanation:A biologist might choose to study the causes of honeybee deaths in beehives. This topic falls under the field of biology as it involves examining the biological factors, ecosystems, and environmental impacts on a species. Biology encompasses the study of living organisms, their interactions within ecosystems, and factors affecting their survival. For instance, a biologist studying honeybee mortality may investigate patterns in bee behavior, health, genetic factors, or the influence of pesticides and other anthropogenic factors on populations.
A specific example of a biologist's work could be an ecologist studying the patterns on the wings of an endangered butterfly species to understand how these patterns help the species escape predators like birds. Researchers in such fields collect data, observe, and analyze patterns to draw conclusions about biological processes and biodiversity. Additionally, factors such as ecological succession and biogeography are critical in such studies.
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4. In the chemical equation H202(aq) → H2O(l) + O2(g), the O2 is a
O
A reactant
Bcatalyst
C
solid
OD product
Answer:
02 is a product
Explanation:
it doesnt take part in chemical reaction so its not reactant.02 doesnt alter rate of chemical reaction so it cannot be catalyst. it is gas it is not solid so it is a product.
Answer: D. Product
Explanation:
In an investigation that uses the scientific method, which step immediately follows asking a question?
O presenting the results
O making observations
O creating a hypothesis
O designing an experiment
Answer:
creating a hypothesis.
Explanation:
you need to have a hypothesis to then start designing the exp.
Answer:
its c)creating a hypothesis.
Explanation:
just took quiz
In what characteristic property must two liquids differ if a mixture of them is to be separated by fractional distillation
Answer:
Boiling point
Explanation:
If the liquids have different boiling points, you can separate them by distillation.
You must carefully control the temperature, so only the liquid with the lower boiling point evaporates, and you can collect it using a condenser.
The boiling points should differ by at least 40 °C for a simple distillation to give good separation.
Which of these time measurements is the smallest?
0.02 seconds
0.02 teraseconds
2,500 milliseconds
25,000 nanoseconds
Answer:
In order to answer the question, we convert the measurements given to a common base unit. For this case, we use seconds.
A) 0.02 seconds
B) 0.02 teraseconds x (10^12 s / 1 terasecond) = 2x10^10 seconds
C) 2,500 milliseconds x (1 s / 1000 ms) = 2.5 seconds
D) 25,000 nanoseconds x (1 x 10^-9 s / 1 nanosecond) = 2.5 x 10^-5 seconds
So ,The correct answer is option " D "
Convert the following temperatures from K to °C.
100 K = °C
273 K = °C
6 K = °C
143°C = K
573°C = K
-173.15
-0.15
-267.15
416.15
846.15
assuming k is kelvins and c is celsius
1. -173.15°c
2. -0.15°c
3. -267.15°c
4. 416.15k
5. 846.15k
PLEASE HELP
An aggregate is one type of land resource. What is an aggregate?
a layer of solid rock found beneath soil
the top layer of soil
a natural mixture of sand, gravel, and crushed stone
a naturally occurring mineral or rock
Answer:
mixture of sand gravel and crushed stone
Answer:
A natural mixture of sand, gravel, and crushed stone.
Explanation:
An aggregate refers to a composite material commonly used in construction, made up of a collection of particles, including sand, gravel, and crushed stone. These materials are often used in the production of concrete, asphalt, and other building materials to provide structural stability and durability. Aggregates are sourced from natural deposits or quarried from larger rock formations and are essential in the construction industry due to their versatility and availability.
What causes geologic events such as earthquakes, volcanic eruptions, and the creation of mountains? A. position of the planets B. atmospheric pressure C. ocean tides D. lithospheric plate movement
I am pretty sure the answer is D. Lithospheric plate movement. :)
D, because without plate movement, there would be no earthquakes or other geologic events.
When sugar is burned, water vapor and carbon dioxide are produced.
A sugar molecule has a specific number of carbon, hydrogen, and oxygen atoms. Use the balanced chemical equation to identify the number of carbon, hydrogen, and oxygen atoms in sugar.
sugar + 12O2 → 11H2O + 12CO2
Sugar has carbon atoms.
Sugar has hydrogen atoms.
Sugar has oxygen atom
Answer:
12 carbon atoms, 22 hydrogen atoms and 11 oxygen atoms.
Explanation:
Using a balanced chemical equation we can identify the number of carbon, hydrogen, and oxygen atoms in sugar.
CxHyOn + 12O₂ → 11 H₂O + 12CO₂
when an equation is completely balanced, then the number of each atom of an element is equal on the reactant side and the product side.
Therefore;
For carbon; x = 12
For Hydrogen; y = (11×2) = 22
For Oxygen; n + (12×2) = 11 + (12×2)
= n + 24 = 11 + 24
n = 11
Therefore the sugar has, 12 carbon atoms, 22 hydrogen atoms and 11 oxygen atoms.
Thus the balanced equation would be;
C₁₂H₂₂O₁₁ + 12O₂ → 11 H₂O + 12CO₂
Answer:
12 carbon atoms, 22 hydrogen atoms and 11 oxygen atoms.
Explanation:
The energy produced by a nuclear reaction comes from:
In the nuclear fusion reaction energy is produced due to remaining mass of the nuclei and in nuclear fission it is released due to breaking of bonds of the nucleus.
What are nuclear reactions?Nuclear reactions are those reactions in which nuclei of two atoms are involved in the reaction.
These are of two types:
Nuclear fission: In this reaction one nuclei will break into two small nuclei and in this process energy is emitted due to breaking of particle into small particles of low mass.Nuclear fusion: In this reaction two nuclei will combine to form one atom of lower mass, and energy is released due to left mass of substance.Hence, energy is produces by the change in mass and breaking of bonds in the nuclear reactions.
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Which of the following solutions will have the lowest freezing point?
a. 1 molar KCl solution
b. 1 molar FeCl3 solution
c. 1 molar CaCl2 solution
d. 1 molar NaCl solution
The answer to this question would be b.
3 things affect the freezing point of water, a constant(Kf), molality(b) and a number of dissolved particles (i).
Kf is a constant so that has the same effect. Because you have 1 mole of everything, molality is also constant.
so the only thing you gotta look after is the number of the dissolved particles which which iron III chloride has the highest
Final answer:
The 1 molar FeCl3 solution will have the lowest freezing point because, upon dissociation, it produces the most particles per kilogram of water, which causes the greatest freezing point depression. So the correct option is b.
Explanation:
The solution with the lowest freezing point is determined by the number of particles produced in the solution upon dissolving the solute. The effect on the freezing point is a colligative property, meaning it depends on the number of solute particles in the solution, not the type of particles. To answer which of the following solutions will have the lowest freezing point — 1 molar KCl, 1 molar FeCl3, 1 molar CaCl2, or 1 molar NaCl — we must consider the dissociation of each compound.
KCl, NaCl, and CaCl2 are all salts that dissociate into ions in solution. KCl and NaCl dissociate into two ions (K+ and Cl- for KCl, Na+, and Cl- for NaCl), so a 1 molar solution of these salts will produce 2 moles of ions per kilogram of water. CaCl2 dissociates into three ions (Ca2+, Cl-, Cl-), resulting in 3 moles of ions per kilogram of water. FeCl3, however, dissociates into four ions (Fe3+, Cl-, Cl-, Cl-), which gives us 4 moles of ions per kilogram of water.
Thus, the solution of 1 molar FeCl3 will have the lowest freezing point because it produces the highest number of dissociated particles, leading to the greatest degree of freezing point depression.
Earth is like a bar magnet. what does this mean about its magnetic poles
A. there are two magnetic north poles
B. there is only a magnetic pole
C. there are both magnetic north and south poles.
D. there is only a magnetic south pole
It's C that's correct.... (the are both magnetic north and south poles)
Earth is like a bar magnet, there are both magnetic north and south poles. Therefore, option (C) is correct.
Why does the earth behave like a bar magnet?A magnet can be defined as an object that has a north pole and south magnetic pole and a magnetic field. The idea that Earth is a magnet, was first proposed in 1600 by a British physician William Gilbert. He represented the earth as a magnet with help of a spherical magnet.
With a compass, the spherical magnet causes a compass needle to behave in a similar way that Earth causes a compass needle to behave. This indicated that a spherical magnet is a good model to represent that the Earth is a magnet.
Earth has north and south magnetic poles from which the North Pole is located at about 80° north latitude. The magnetic field is strongest at the poles, and magnetic field lines of magnetic force move from the north pole to the south magnetic pole.
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Sodium-24 has a half life how much sodium-24 will remain in an 18 g sample after 75 hours
Answer:
[tex]\boxed{\text{0.56 g}}[/tex]
Explanation:
The half-life of Na-24 (15 h) is the time it takes for half of it to decay.
After one half-life, half (50 %) of the original amount will remain.
After a second half-life, half of that amount (25 %) will remain, and so on.
We can construct a table as follows:
No. of Fraction Mass
half-lives t/da Remaining Remaining/g
0 0 1 18
1 15 ½ 9.0
2 30 ¼ 4.5
3 45 ⅛ 2.2
4 60 ⅟₁₆ 1.1
5 75 ⅟₃₂ 0.56
6 90 ⅟₆₄ 0.28
We see that [tex]\boxed{\textbf{0.56 g}}[/tex] remain after five half-lives (75 h).
The half-life of Sodium-24 is 15 hours. Using this information, you can determine that approximately 0.5625g of the initial 18g of Sodium-24 will remain after 75 hours.
In order to determine the amount of Sodium-24 remaining after 75 hours, we first need to know the half-life of Sodium-24, which is approximately 15 hours. The term 'half-life' refers to the period of time it takes for half of the initial amount of a radioactive substance to decay.
After one half-life (15 hours), half of the 18g of Sodium-24 would remain, which is 9g. After the second half-life (30 hours), half of the 9g would remain, which is 4.5g. After the third half-life (45 hours), half of 4.5g would remain, which is 2.25g. After the fourth half-life (60 hours), half of 2.25g would remain, which is about 1.125g. Finally, after the fifth half-life (75 hours), half of 1.125g would remain, which is approximately 0.5625g. Thus, after 75 hours, 0.5625g of the initial 18g of Sodium-24 would remain.
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calculate the pressure in atm occupied by this gas at 42.5 liters,65c,1.52 moles
Answer:
0.9925 atm.
Explanation:
We can use the general law of ideal gas: PV = nRT.
where, P is the pressure of the gas in atm (P = ??? atm).
V is the volume of the gas in L (V = 42.5 L).
n is the no. of moles of the gas in mol (n = 1.52 mol).
R is the general gas constant (R = 0.0821 L.atm/mol.K),
T is the temperature of the gas in K (T = 65°C + 273 = 338.0 K).
∴ P = nRT/V = (1.52 mol)(0.0821 L.atm/mol.K)(338.0 K)/(42.5 L) = 0.9925 atm.
An Alcohol and an organic acid are combined to form water and a compound with a pleasant odor. This reaction is an example of what?
Answer:
This reaction is an example of forming ester "Esterification".
Explanation:
This reaction is an example of forming ester "Esterification".In which an alcohol and an organic acid are reacted to produce ester (which gives fruit like pleasant odor).The most commonly ester is ethyl-ethanoate:Ethanol + acetic acid → ethyl-ethanoate + water.
C₂H₅OH + CH₃COOH → CH₃COOC₂H₅ + H₂O.
Upon combustion, a compound containing only carbon and hydrogen produces 2.49 g CO2 and 0.763 g H2O . Find the empirical formula of the compound
Answer:
CH2.
Explanation:
The mass of C in the CO2 = 2.49 * 12/(12+32) = 0.6791 g
The mass of Hydrogen in the water = 2 * 1.008 / (2.016 + 16) = 0.1119 g.
Ratio of H to O is 0.1119/ 1.008 : 0.6791/12
= 0.111 : 0.0566
= 2 : 1
The empirical formula is CH2
A container of hydrogen at 172 kpa was decreased to 85.0 kpa producing a new volume of 765 mL. What was the original volume
Answer:
[tex]\boxed{\text{378 mL}}[/tex]
Explanation:
The temperature and amount of gas are constant, so we can use Boyle’s Law.
[tex]p_{1}V_{1} = p_{2}V_{2}[/tex]
Data:
[tex]\begin{array}{rclrcl}p_{1}& =& \text{172 kPa}\qquad & V_{1} &= & \text{?} \\p_{2}& =& \text{85.0 kPa}\qquad & V_{2} &= & \text{765 mL}\\\end{array}[/tex]
Calculations:
[tex]\begin{array}{rcl}172V_{1} & =& 85.0 \times 765\\172V_{1} & = & 65 025\\V_{1} & = &\textbf{378 mL}\\\end{array}\\\text{The original volume was } \boxed{\textbf{378 mL}}[/tex]
Final answer:
Using Boyle's Law, which states that at a constant temperature the pressure and volume of a gas are inversely related, the original volume of hydrogen in the container can be calculated to be approximately 2211 mL.
Explanation:
To find the original volume of the hydrogen gas, we apply Boyle's Law, which states that the pressure of a gas multiplied by its volume is constant at constant temperature (P1V1 = P2V2). In the given problem, we have an initial pressure (P1) of 172 kPa, an unknown original volume (V1), a final pressure (P2) of 85.0 kPa, and a final volume (V2) of 765 mL.
Using the formula, we have:
172 kPa × V1 = 85.0 kPa × 765 mL
Now we solve for V1:
V1 = (85.0 kPa × 765 mL) / 172 kPa
V1 = 380.25 kPa·mL / 172 kPa
V1 = 2210.7558 mL
Therefore, the original volume of the hydrogen gas was approximately 2211 mL.
123.4 grams of iron to moles of iron
Answer:
2.209687527979228
Explanation:
Hope this help!
Select the correct answer from each drop-down menu.
What is the chemical name of this compound?
Na2S:
Answer:
Sodium Sulphide.
Explanation:
The chemical name is sodium sulphide. The valency of the sulphide ion is 2 while the valency of sodium is 1 . That is why the molecule contains 2 sodium ions.
Answer: sodium sulphide.
Explanation:
[tex]Na_2S[/tex] is an ionic compound because sodium element is a metal and sulphur element is a non-metal. The bond formed between a metal and a non-metal is always ionic in nature.
The nomenclature of ionic compounds is given by:
1. Positive is written first.
2. The negative ion is written next and a suffix is added at the end of the negative ion. The suffix written is '-ide'.
Hence, the name of [tex]Na_2S[/tex] is sodium sulphide.
Therefore, the correct answer is sodium sulphide.
Which statement describes a chemical property of iodine?
Iodine's chemical properties include solubility in various solvents to form violet or brown solutions, and its ability to act as a weak Lewis acid towards iodide ions. It is also the least reactive halogen and does not oxidize other halide ions.
Explanation:Iodine exhibits several chemical properties. It is soluble in chloroform, carbon tetrachloride, carbon disulfide, and many hydrocarbons, forming violet solutions. It dissolves slightly in water, giving brown solutions. Iodine is also soluble in aqueous solutions of iodides, where it forms brown solutions due to its ability to act as a weak Lewis acid towards the iodide ion. In addition, iodine is the least reactive halogen and does not oxidize other halide ions.