Answer:
An endothermic reaction is identified by noting the drop in temperature in the system.
Explanation:
An endothermic reaction occurs by absorbing heat energy from the environment( apparatus and solution). Once the energy in the surrounding reduces the temperature drops. The energy absorbed is used to form new bonds. The energy absorbed is directly proportional to the temperature drop.
Answer:
An endothermic reaction absorbs heat from its surroundings.
Explanation:
An example is the reaction of acetic acid with baking soda.
Three ways to tell if a reaction is endothermic:
Do the experiment. The system cools down, and you can use a thermometer or your hand to tell that the flask becomes colder .Heat will appear as a reactant in the chemical equation:CH₃COOH + NaHCO₃ + heat ⟶ CH₃COONa + H₂O + CO₂ The sign of ΔH is positive. N₂ + 2O₂ ⟶ 2NO₂ ; ΔH = +33.1 kJ·mol⁻¹What can form as a result of a chemical reaction?
What can form as a result of a chemical reaction?
compounds
isotopes
alpha particles
beta particles
Answer:
Compounds
Explanation:
Chemical reactions involving more than one element mostly give rise to compounds when transfer of electrons occurs.
The compounds are as a result of the combination of the individual elements and radicals.
Isotopes occur naturally while alpha (α) and beta (β) particles are as a result of nuclear reactions.
Answer: compounds
Explanation:
A physical reaction is defined as the reaction in which a change in shape, size takes place. No new substance gets formed in these reactions.
A chemical reaction is defined as the reaction in which a change in chemical composition takes place. A new substance or compound is formed in these reactions.
[tex]2H_2+O_2\rightarrow 2H_2O[/tex]
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass. It can be decomposed into simpler constituents using chemical reactions. Example: water [tex]H_2O[/tex]
Isotopes, alpha and beta particles are formed in nuclear reactions.
What is the concentration of a saturated solution of SrSO4? SrSO4 has a Ksp of 3.2 x 10–7
Final answer:
The concentration of a saturated solution of SrSO4 can be calculated by taking the square root of the Ksp value, in this case, sqrt(3.2 x 10⁻⁷), to find the solubility 's', which represents the concentration of both Sr²+ and SO₄⁻²ions in mol/L.
Explanation:
Calculating the Saturation Concentration of SrSO₄
To determine the concentration of a saturated solution of SrSO₄, given its Ksp (solubility product constant) of 3.2 x 10⁻⁷, we set up the equilibrium expression for the dissolution of SrSO₄:
SrSO₄(s) ⇌ Sr²⁺(aq) + SO₄²⁻(aq)
For each mole of SrSO4 that dissolves, one mole of Sr²⁺ and one mole of SO₄⁻²are produced in the solution. Therefore, if 's' represents the solubility of SrSO₄in molarity (mol/L), then the concentrations of Sr⁺² and SO₄⁻² at saturation are both 's' M. Substituting 's' into the Ksp expression:
[tex]Ksp = [Sr^{2+}][SO4^{2-}] = s * s = s^{2}[/tex]
Solving for 's', we take the square root of Ksp:
s = √Ksp = √ 3.2 x 10⁻⁷,
Calculating this gives us the saturation concentration 's' of SrSO₄ in the solution.
Therefore, the concentration of the saturated solution of SrSO₄ is the value of 's' after solving the above equation.
(WILL GIVE BRAINLIEST ANSWER) A runner burns 10 kilocalories per minute. If the runner completes a race in 1 hour and ten minutes, how many kilocalories does he burn during the entire race? How many grams of pasta would provide him with this much energy? (1 gram of pasta gives 4.06 kilocalories of energy)
Answer:
700 kilo calories was burnt during the entire race.
172.41 grams of pasta would provide him with 700 kcal energy.
Explanation:
Rate of burning calories = R = 10 kcal/min
Number of calories burnt in 1 hour and 10 minutes = x
Duration of race = t = 1 hour + 10 min
1 hour = 60 minutes
t = 60 min + 10 min = 70 min
[tex]x=R\times t=10 kcal/min\times 70 min=700 kcal[/tex]
700 kilo calories was burnt during the entire race.
Number of calories in 1 gram of pasta = 4.06 kcal/g
Amount of pasta with 700 kcal = m
[tex]m\times 4.06 kcal/g=700 kcal [/tex]
[tex]m=\frac{700 kcal}{4.06 kcal/g}=172.41 g[/tex]
172.41 grams of pasta would provide him with 700 kcal energy.
The formation of a solid, also known as a _____, is an indication of a chemical change. precipitate particulate particle powder
Answer:
Precipitate
Explanation:
Precipitation is actually a chemical reaction that occurs when a solid form is produced from a solution. The solid form is called the precipitate if precipitation occurs in a liquid solution. Precipitates formed are generally, insoluble. This type of reaction can be used to remove salts from a solution, like in the process of purification.
Answer:
Answer: precipitate
Explanation: Chemical change is a change in which the chemical composition of the atoms changes. The following changes are seen when chemical reaction takes place:
1) Release or absorption of heat
2) Formation of solid or a precipitate
3) Change in color
4) Production of gas
Explanation:
what type of circuit is illustrated
a) series circuit
b) short circuit
c) open circuit
d) parallel circuit
A sample of an unknown volatile liquid was injected into a Dumas flask (mass of flask=
27.0928 g. Volume of the flask is 0.1040L) and heated until no visible traces of the
liquid could be found. The flask and its contents were then rapidly cooled and
reweighed (mass of flask + vapor = 27.4593 g). The atmospheric pressure and
temperature during the experiment were 0.976 atm and 18.0°C, respectively. The
unknown volatile liquid was_ (make sure you use the proper name for this
organic compound)
The unknown volatile liquid in your Dumas flask is most likely water due to its molar mass of approximately 18 g/mol
Explanation:The identity of the unknown volatile liquid in your Dumas flask can be determined using the ideal gas law equation PV=nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in kelvins. By rearranging this equation to n=m/M, we can find the molar mass (M). With your provided figures (change in mass = 27.4593 g - 27.0928 g, V=0.104L, P=0.976 atm, T=18°C + 273=291K), we find M=~18 g/mol. This molar mass is most closely correlated to the organic compound known as Water (H2O).
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A triple covalent bond involves two atoms sharing three pairs of electrons.
True
False
Covalent bonds are formed by electron sharing. One single covalent bond shares a pair of electrons. Hence a triple bond is sharing three pairs of electrons. Thus, the statement is true.
What is covalent bond?Covalent bond is a type of bond formed by the sharing of electrons between two atoms. The two atoms might be of comparable electronegativities.
Atoms which are deficient in electrons will gain or share electrons with other atoms. Two atoms both are electron deficient will share their valence electrons each other.
A single covalent bond is the two electrons shared by each atoms in the bond thus a pair of electrons. Double bond is thus two pair or four electrons. Therefore, a triple covalent bond involves two atoms sharing three pairs of electrons.
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Given [OH-] = 5.5 x 10-10M Find: [H3O+] and pH Is this acidic, basic or neutral?
Answer:
Explanation:
Given parameters:
Hydroxide ion concentration = 5.5 x 10⁻¹⁰M
Unknown:
concentration of hydroxonium ion [H₃O⁺]= ?
pH = ?
Solution
To determine the concentration of the hydroxonium ion, we know that from the ionic product of water:
[H₃O⁺][OH⁻]= 10⁻¹⁴
[H₃O⁺] = [tex]\frac{10^{-14} }{OH^{-} }[/tex]
[H₃O⁺] = [tex]\frac{10^{-14} }{5.5 x 10^{-10} }[/tex]
[H₃O⁺] = 1.8 x 10⁻⁵M
To find the pH of the solution, we use the expression below:
pH = -log₁₀[H₃O⁺]
pH = -log₁₀ 1.8 x 10⁻⁵ = -(-4.74) = 4.7
Since the pH of the solution is 4.7, it is acidic.
What does the oxidizing agent do in a redox reaction?
A. Oxidizes another atom
B. Gets oxidized
C. Donates electrons
D. Reduces another atom
The oxidizing agent do in a redox reaction is "donates electrons".
What is oxidizing agent?A material that obtains electrons and would be reduced, which results in a drop in oxidation state, would be an oxidizing agent. The other substance oxidized to form due to it.
What are electrons?The smallest elemental component of an atom, the electron has a negative charge. In a neutral atom, there are an equal number of protons as well as electrons.
Therefore, the oxidizing agent do in a redox reaction is "donates electrons".
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Answer:
A. Oxidizes another atom
Explanation:
Just did the quiz and guessed B, but got it wrong, and showed me that A is correct.
Select all that apply to temperature and the kelvin scale.
-Scientists have been able to cool substance to absolute zero.
-0 K is equal to -273 degrees Celsius.
-Gas can have a volume of 0.
-The term “degree” is not used with the Kelvin scale.
-Cryogenics is the study of very low temperatures and their effects.
Answer: Option (2), (4) and (5)
Explanation:
Absolute zero refers to the temperature from which there occurs no cooling. Scientists have not been able to cool any substance upto its absolute zero temperature. A temperature close to the absolute zero temperature is attained but it never exactly reaches the absolute temperature.
For the conversion from celsius scale to kelvin or from kelvin to celsius scale, it is universally taken to be 0 K= -273°C.
Gas can never be zero volume because gas is a matter and certain composition and thus has its own volume.
In Kelvin scale, k is used whereas in celsius scale, degree (°) is used.
Cryosphere refers to the study of the materials and their characteristics at a relatively very low temperature.
Thus, the correct answers are option (2), (4) and (5).
Neutral atoms of argon, atomic number 18, have the same number of electrons as each of the following items except: Cl- S -2 K+ Ca +2 Ne
Answer:
Ne.
Explanation:
Neutral argon, atomic number 18, has 18 electrons.
Cl⁻:
Neutral atom of Cl, atomic number 17, has 17 electrons.
When it gains electron and be Cl⁻, then it has 18 electrons a neutral Ar.
S²⁻:
Neutral atom of S, atomic number 16, has 16 electrons.
When it gains 2 electrons and be S²⁻, then it has 18 electrons a neutral Ar.
K⁺:
Neutral atom of K, atomic number 19, has 19 electrons.
When it losses electron and be K⁺, then it has 18 electrons a neutral Ar.
Ca²⁺:
Neutral atom of Ca, atomic number 20, has 20 electrons.
When it losses 2 electrons and be Ca²⁺, then it has 18 electrons a neutral Ar.
Ne:
It is a noble gas that has 10 electrons.
So, the right choice is: Ne.
the answer is ne
Explanation:
What is the total mass of copper consumed when 16.0 moles of water are produced?
3Cu + 8HNO3 → 3Cu(NO3)2 + 2NO + 4H2O
Answer:
762.55 g.
Explanation:
For the balanced reaction:3Cu + 8HNO₃ → 3Cu(NO₃)₂ + 2NO + 4H₂O.
It is clear that 3 mol of Cu reacts with 8 mol of HNO₃ to produce 3 mol of Cu(NO₃)₂, 2 mol of NO, and 4 mol of H₂O.
We need to calculate the no. of moles of copper consumed when 16.0 moles of water are produced:Using cross multiplication:
3 mol of Cu produce → 4 mol of H₂O, from stichiometry.
??? mol of Cu produce → 16 mol of H₂O.
∴ no. of moles of Cu needed = (3 mol)(16 mol)/(4 mol) = 12 mol.
Now, we can get the mass of Cu needed:∴ mass of Cu = (no. of moles)(atomic mass of Cu) = (12 mol)(63.546 g/mol) = 762.55 g.
If you have 35.0g of Na and 100.0g of Cl2, what is the maximum amount of NaCl that you can produce?
2Na + Cl2 → 2NaCl
57.7 g
165 g
75.8g
89.0 g
HELPP PLEASE
Answer:
89.0 g.
Explanation:
The balanced chemical equation between CuO and HCl is:2Na + Cl₂ → 2NaCl,
It is clear that 2 mol of Na react with 1 mol of Cl₂ to produce 2 mol of NaCl.
Firstly, we need to calculate the no. of moles of (35.0 g of Na) and (100.0 g Cl₂):
no. of moles of Na = mass/molar mass = (35.0 g)/(22.989 g/mol) = 1.522 mol.
no. of moles of Cl₂ = mass/molar mass = (100.0 g)/(70.906 g/mol) = 1.41 mol.
From the balanced equation: Na reacts with Cl₂ with (2: 1) molar ratio.
∴ 1.522 mol of Na "limiting reactant" reacts completely with 0.761 mol of Cl₂ "excess reactant".
To calculate the mass of the produced salt (CuCl₂):
2 mol of Na produces → 2 mol of NaCl, from stichiometry.
∴ 1.522 mol of Na produces → 1.522 mol of NaCl.
∴ The mass of the produced salt (NaCl) = (no. of moles)(molar mass) = (1.522 mol)(58.44 g/mol) = 88.95 g ≅ 89.0 g.
Final answer:
To find the maximum amount of NaCl produced from 35.0g of Na and 100.0g of Cl2, determine the limiting reactant and calculate the moles to find the answer of 75.8g.
Explanation:
To determine the maximum amount of NaCl that can be produced from 35.0g of Na and 100.0g of Cl2, you need to identify the limiting reactant in the reaction.
The molar mass of NaCl is 58.44g/mol, so we can calculate the moles of Na and Cl2 to see which one will run out first, limiting the amount of NaCl produced.
The maximum amount of NaCl that can be produced is 75.8g.
How many moles of H are in 0.9 mol C21H23NO5? Enter your answer to 1 decimal place.
Answer:
Explanation:
I mol of C21H23NO5 Contains 23 moles of H
0.9 mol of C21H23NO5 contains 23*0.9 mols of H
mols of H = 20.7
Given: K = °C + 273.15
What is the temperature of the flame in degrees Celsius?
You measure the flame of a candle and get a reading of 1,376.06 K. This value is equal to
Answer:
Tk=TC+273.15
so
1376.06=Tc+273.15
TC=1376.06-273.15
TC= =1,102.91
Answer: 1102.91 ºC
Explanation: To solve this problem, we only need to isolate the temperature in Celsius from the given equation:
TK=TºC+273.15
TºC=TK-273.15
now, replacing the temperature of the flame in K:
TºC=1376.06-273.15
TºC=1102.91 ºC
How are evaporation and sublimation similar?
A Both involve the formation of a gas.
B Both release energy to the surroundings.
C Both take place throughout a solid.
D Both take place at the surface of a liquid.
Answer:
Both involve the formation of gas.
Answer:
A Both involve the formation of a gas.
Explanation:
Sublimation occurs when it passes from the solid-state to the gaseous state without going through the liquid state.
Evaporation occurs when it passes from the liquid state to the gaseous state.
These processes have in common that the final state they reach is the gaseous state.
How many molecules and atoms of oxygen are present in 5.6 liters of oxygen (O2) at STP?
how many electrons does silver have to give up in order to achieve a sido noble gas electron configuration
Answer:
Silver has to give up one electron.
Explanation:
Silver is a transition element and has a partially filled 4d- orbital having 9 electrons and a 5s orbital having 2 electrons in it. In order to achieve stability, silver must have completely filled d-orbital having a maximum number of 10 electrons in it.
Therefore, one electron from 5s orbital jumps to 4d orbital to make it stable. Now, 5s orbital has only one electron, and it will be easy for silver to lose this electron to attain a stable electronic configuration.
A stable atom that has a large nucleus most likely contains
1. more neutrons than protons.
2.more protons than neutrons.
3.equal numbers of protons and neutrons.
4.changing numbers of protons and neutrons.
Answer:
3. Equal numbers of protons and neutrons
Explanation:
The nucleus becomes unstable if the ratio of protons to neutrons is less than 1:1 or more than 1:1.5.
The most stable nucleus has a neutron proton ratio of 1:1 which means that they can not release a neutron or a proton to decay.
Nucleus 3 is therefore the most stable.
Answer:
1. more neutrons than protons
Explanation:
I got it right on edge
which of these energy resources does not pollute when used
Answer:
Solar power: solar power converts the sun's energy into energy we can use.Nuclear power: heat is used to generate steam that drives a steam turbine connected to a generator that produces electricity.Hydroelectric energy: hydroelectric power plants use a dam on a river to store water in a reservoir. Water released from the reservoir flows through a turbine, spinning it, which in turn activates a generator to produce electricity.Wave energy: wave energy proves itself to be a valuable contributor to alternative energy fuel sources with wave energy converters.Biofuels: biofuels make use of animal and plant life to create energy.Natural gas: emits greenhouse gases, but the amount is lower than with fossil fuels.Geothermal power: geothermal power is about extracting energy from the ground Wind energy: it uses wind as energy and it makes use of a renewable source and generates no waste.Biomass energy: biomass energy comes in a number of forms. For example, burning wood has been used for thousands of years to create heat, but more recent advancements have also seen waste, such as that in landfills, and alcohol products used for similar purposes.Tidal energy: tidal energy uses the power of water to generate energyHydrogen gas: hydrogen is a completely clean burning fuel. Once produced, hydrogen gas cells emit only water vapor and warm air.__________ is the most widely used method of formally measuring public opinion.
A. Face-to-face interviewing
B. Polling
C. The census
D. Democratic elections
Answer:
B. Polling is the most widely used method of formally measuring public opinion.
Answer:
B. Polling
Explanation:
The most widely sued method to obtain data without any time lag or any sort of problem and the privacy of the respondents are considered accordingly. The public opinion cannot take face to face thus this method is most suitable for large masses. It helps to gather data quickly is cost-effective and does not allow much biasness. Polling can be done on any subject any topic.lons are defined as ____
a) atoms that have lost or gained an electron and have a charge.
b)atoms that are bonded to other atoms of the same element
c)neutral atoms
d)nuclear atoms
Answer:A
Explanation: ion
an atom or molecule with a net electric charge due to the loss or gain of one or more electrons.
Answer:
Option A) Atoms have lost or gained an electron and have a charge
Explanation:
The result of a loss or gained electron can cause a large or lesser number of protons than the electrons, which causes a charge imbalance because protons have a positive charge and electrons have a negative charge. If the number of protons or the number of electrons is unequal, then it means that the atom has a charge, and is an ion. It is a cation if it lost an electron such that it has a positive charge and it is an anion if it gained an electron such that it has a negative charge.
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Which question cannot be answered scientifically?
A. How many particles do two gases at the same temperature and pressure contain?
B. What happens to a gas at standard temperature and pressure?
C. How does a gas react when heated to 100 degrees Celsius?
D. What happens to a sample of gas at absolute zero?
Answer:
b. What happens to a gas at standard temperature and pressure?
Explanation:
YEET
what is the best describtion of the side of the moon that faces earth?
Answer:
It would change
Explanation:
The elements in group 17 of the periodic table are all called halogens. All halogens have the same
atomic number.
atomic mass.
number of possible isotopes.
number of valence electrons.
Answer:
They have the same number of valence electrons
Explanation:
The groups on the periodic table are the vertical lines of groups. In group 18 the elements are known as noble gases. They have all 8 valence electrons. As you go to the left the groups have one less valence electron. Group 17 has 7 valence electrons.
The elements in group 17 of the periodic table are called halogens. All halogens have the same number of valence electrons.
What are Halogens?
Elements that have 7 electrons in their last subshell and belong to group 17 are known as Halogens. Names of different halogens are:
FluorineChlorineBromineIodineAll the elements of Group 17 contain 7 valence electrons.
Fluorine is the most electronegative element in the periodic table. Fluorine is a highly toxic gas and breathing the fluorine can be lethal for human beings. People when exposed to fluorine gas can experience arthritis.
Chlorine gas is also a toxic gas for human beings.
Bromine is less toxic than chlorine and fluorine. Bromide has a lethal dose of 30 mg.
Iodine is also somewhat less toxic. Iodine is also used as a Tincture of Iodine. Exposure to Iodine can lead to irritation in the eyes and lungs.
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How many grams of Na2O are produced when 70.7 g of Na reacts?
4Na(s)+O2(g)→2Na2O(s)
Answer:
95.3 grams.
Explanation:
Relative atomic mass data from a modern periodic table:
Na: 22.990;O: 15.999.How many moles of Na are consumed?
[tex]M(\mathrm{Na}) = \rm 22.990\; g\cdot mol^{-1}[/tex].
[tex]\displaystyle n(\mathrm{Na}) = \frac{m(\mathrm{Na})}{M(\mathrm{Na})} = \rm \frac{70.7\; g}{22.990\;g\cdot mol^{-1}}=3.07525\;mol[/tex].
How many moles of [tex]\mathrm{Na_2 O}[/tex] formula units will be produced?
Consider the ratio between the coefficient of [tex]\mathrm{Na_2 O}[/tex] and that of [tex]\mathrm{Na}[/tex] in the equation:
[tex]\displaystyle \frac{n(\mathrm{Na_2 O})}{n(\mathrm{Na})} = \frac{2}{4} = \frac{1}{2}[/tex].
As a result,
[tex]\displaystyle n(\mathrm{Na_2 O}) = n(\mathrm{Na}) \cdot \frac{n(\mathrm{Na_2 O})}{n(\mathrm{Na})} = \rm \frac{1}{2}\times 3.07525\;mol = 1.53763\; mol[/tex].
What will be the mass of that many [tex]\mathrm{Na_2 O}[/tex]?
Formula mass of [tex]\mathrm{Na_2 O}[/tex]:
[tex]M(\mathrm{Na_2 O}) = \rm 2\times 22.990 + 15.999 = 61.979\; g\cdot mol^{-1}[/tex].
[tex]m(\mathrm{Na_2 O}) = n(\mathrm{Na_2 O})\cdot M(\mathrm{Na_2 O}) = \rm 1.53763\; mol\times 61.979\; g\cdot mol^{-1} \approx 95.3\; g[/tex].
Answer: 95,3 g. would be produced, if the mass of Na = 70,7 g.
Which of these natural resources is non-renewable A.Corn B.wind c.geothermal D.natural gas
Answer: D. Natural Gas
Explanation: There is only a limited supply of natural gas on our planet, and if we use up that supply, there is no way of more natural gas being generated.
The correct answer would be: D. Natural gas
This would be the correct answer since natural gases are considered a fossil fuel. The other options are renewable resources. Corn can be reproduced. Wind is a source of energy which makes it renewable. Geothermal is also a renewable resource since its heat is from the earth's core which could be used multiple times.
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Equivalent weight of h2co3
Answer: 62.02478 g/mol
Explanation:
Answer:
31 grams per equivalent.
Explanation:
The valence of carbonic acid (H2CO3) is two (there are two replaceable hydrogen ions). The molecular weight of H2CO3 is: 2*1 + 12 + 3*16 = 62 g/mol. Therefore, the equivalent weight is: 62/2 = 31 grams per equivalent.
How are magnets made? What raw materials are required?
Hello There!
Image Attached Below
Answer:
The most common magnetic metals are iron, nickel, and cobalt. Alloys that contain one or more of those elements are usually ferromagnets, meaning that the magnetic orientations of nearby atoms line up with each other on their own to make little magnetic domains
A medium of free floating positive and negative charges are called ?
Answer:
Plasma
Explanation:
Mostly this occurs at very high temperatures that cause atoms to lose electrons. Plasma is therefore a gas but of ions. Plasma can conduct electricity and can be influenced by magnetic fields. Plasma occurs mostly in stars where it is the dominant state of matter.
Answer:
Plasma
Explanation:
Answer via Founder's Education/ Educere. Plasma fits the definition of the answer because it contains both positive and negitive free-flowing charges.