I answered as many as I could but can someone double check my answers and help me with the rest?
1. Example Bond Energies of Ionic Compounds
Li–F = 1036 kJ/mol
Li-Br = 807 kJ/mol
Na-F= 923 kJ/mol
Na-Br = 747 kJ/mol
Given the general trend with bond energies, which of the compounds would have the smallest bond energy?
Cs-F
Cs-Br
K--Br ****
2.Based on the differences in electronegativities, with which atom is francium (Fr) most likely to form an ionic bond?(1 point)
Fr–Cl = 2.46
Fr–At = 1.50
Fr–I = 1.96
Fr–Se = 1.76 ***
3. Which statement is the best description of the energy found in molecules of water? (1 point)
Hotter molecules have more kinetic energy.
A molecule's temperature is not connected to its energy.
Colder molecules have more thermal energy.
Colder molecules have more kinetic energy
4. When potassium permanganate and glycerol react, the potential energy of the products is less than the potential energy of the reactants. Which statement about this reaction is correct?(1 point)
The activation energy of the system is negative.
The total potential energy of the system is constant.
The reaction is endothermic.
The reaction is exothermic.
5.Hydrochloric acid and sodium hydroxide react to produce water and sodium chloride in an endothermic reaction. Which statement must be true of the reaction?(1 point)
More bond energy is absorbed on the reactants side than is released on the products side.
The total bond energy of water and sodium chloride is greater than the total bond energy of hydrochloric acid and sodium hydroxide. ****
The bond energy used to break the bonds in hydrochloric acid and sodium hydroxide is less than the energy released to form the bonds in water and sodium chloride.
The energy of each bond in water and sodium chloride is greater than the energy of each bond in hydrochloric acid and sodium hydroxide.
6. Imagine a graph. The x-axis is labeled "Time" and is measured in seconds, and the y-axis is labeled "Potential Energy" and is measured in kilojoules. The slope starts at 0 seconds with a plateau at 25 kJ. This plateau is labeled "Reactants." The slope then rises to a peak labeled "Activation Energy" at 78 kJ. Finally the slope drops to a plateau at 14 kJ and is labeled "Products."
What does the graph described above represent?
an endothermic reaction
rate of Reaction graph
an exothermic reaction ****
a phase change graph
7. Endothermic reactions absorb a lot of energy. Exothermic reactions give off a lot of energy. Which type of reaction has a higher activation energy? Which one takes more energy to break up the bonds of the reactants?(1 point)
Endothermic reactions have a higher activation energy. Exothermic reactions require more energy to break up the bonds of the reactants.
Exothermic reactions have a higher activation energy. Endothermic reactions require more energy to break up the bonds of the reactants.
Exothermic reactions have a higher activation energy. Exothermic reactions require more energy to break up the bonds of the reactants.
Endothermic reactions have a higher activation energy. Endothermic reactions require more energy to break up the bonds of the reactants.
8. Why is thermal energy (heat) required to freeze ice into crystals?(1 point)
Heat must be absorbed by the reactants and the products.
Heat must be released by the products in order to convert from the reactants.
Heat must be absorbed by the products in order to convert from the reactants.
Heat must be released by the reactants and the products. ****
9. Cobalt ions form complex ions with water and chloride as shown in the reaction. The left side of the reaction is pink, and the right side of the reaction is blue.
Co(H2O)62+ + 4Cl– + heat ⇄ CoCl42–+ 6H2O
Which statement about the system at equilibrium is correct?
Cooling a purple solution will turn it pink.
Adding water to a purple solution will turn it blue.
Adding hydrogen chloride (HCl) to a blue solution will turn it purple.
Heating a blue solution will turn it purple.
10. Why are rubber and metal both useful while making wire?(1 point)
Both are good insulators, but one is flexible while the other is rigid.
Both are flexible, but one reflects electromagnetic waves well while the other transmits them.
Both are good insulators, but one is more ductile than the other.
Both are flexible, but one conducts electricity while the other insulates.
11. A pharmaceutical company wants to extract an ingredient from pomace supplied by a certain food processing plant. Which process is the most efficient with the lowest environmental impact?(1 point)
high pressure, high temperature water extraction
catalyst extraction
enzyme extraction
organic solvent extraction
12. Which option is a modern reason for optimizing the mining process?(1 point)
increasing production efficiency
reducing waste
reducing environmental impact****
increasing profits
Use the reaction to answer the question.
Fe2O3 + 3H2SO4
13. How many atoms of oxygen will be found in the product(s) of the reaction?
3
12
4
15****
14. Use the table and equation to answer the question.
Element Atomic Mass (amu)
hydrogen 1
carbon 12
oxygen 16
CH4 + 2 O2 → CO2 + 2 H2O
The law of conservation of matter states that matter cannot be created nor destroyed. How does the balance equation above demonstrate this law?
The number of molecules, number of atoms, and mass of reactants and products are equal.
The number of molecules, number of atoms, and type of elements are equal.
The number of molecules, type of elements, and mass of reactants and products are equal. ****
The number of atoms, type of elements, and mass of reactants and products are equal.
Elements A and B react according to the following balanced equation.
3A2 + 2B → 2A3B
15. The molar mass of element A is 4 g/mol. The molar mass of element B is 16 g/mol. When the initial mass of element A is 48 grams, which mass of element B should be present?
64 grams
96 grams
192 grams
128 grams
16. Use the table of molar masses to answer the question.
Element Molar Mass (g/mol)
silicon 28.09
oxygen 16.00
How many molecules of silicon dioxide (SiO2) are there in a 15-gram sample?
1.251x10^23
1.503x10^23
2.049x10^23
6.022x10^23
17. Which statement about the number of protons and neutrons in a nuclear change is correct?(1 point)
The relative numbers of protons and neutrons can differ before and after the change, but the total number of those particles remains the same.
The relative numbers of protons and neutrons are the same before and after the change.
The total atomic mass before and after the change remains the same, but the total charge is different.
The total charge before and after the change remains the same, but the total atomic mass is different.***
18. Which statement accurately describes nuclear fission? (1 point)
Fission is a process in which two or more nuclei combine to form a larger nucleus.***
Fission is a process in which an unstable nucleus releases matter and energy.
Fission is a process in which a large nucleus is split into smaller nuclei.
Fission is a process in which two or more atoms combine chemically.
19 A nucleus decays to produce a nucleus with one additional proton. Which type of decay did the nucleus undergo?(1 point)
beta-plus decay
gamma decay
alpha decay
beta-minus decay***
20 Which type of decay is a form of nuclear fission?(1 point)
beta-minus decay ***
alpha decay
gamma decay
beta-plus decay
21. Why do some atmospheric gases act as greenhouse gases, while others do not?(1 point)
Naturally occurring gases do not act as greenhouse gases, while human-made gases do.
The industrial revolution changed the components of the atmosphere, causing some gases to become greenhouse gases.
Greenhouse gases have more than two atoms, allowing them to vibrate and release radiation, warming the atmosphere.****
Non-greenhouse gases are made of only one element, like nitrogen or oxygen.
22 Which option correctly identifies a cause and consequence of water pollution?(1 point)
cause: particulates
consequence: smog
cause: runoff of pesticides
consequence: global warming
cause: acid rain
consequence: destruction of crops ***
cause: chlorofluorocarbons
consequence: depletion of ozone layer
23. Which outcome is the most likely result of eutrophication of a waterway?
reduction of the algae population
overpopulation of aquatic plants
toxic bacteria in the water supply ***
reduced storm runoff
24. Despite fracking being a controversial process in the fuel industry, it is still used today. Why?
There is little environmental harm done to the land.
It is inexpensive to do.***
It can be done on lands no one wants.
It reaches hard to get to oil and gas deposits.
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