Question

Energy that moves through space and does not require matter to touch in order to be transferred moves through _______________.
Conduction.
Convection.
Radiation.

If a chemical reaction results in an overall energy change of -3,271 kJ/mol, how would the reaction be described?
Endothermic, there is a large amount of energy present.
Exothermic, there is a large amount of energy released to the surroundings.
Exothermic, there is a large amount of energy absorbed by the reaction.

In the following reaction, NaCl (s) + energy → Na+ (aq) + Cl-(aq), what role did the energy play as a “reactant” on the left side of the equation?
It was energy put into the solid in order to make the particle reach activation energy to break apart.
It was energy absorbed from the system that was already present.
It was energy released from the reactants to the surroundings.


Which statement is true?
Energy must always be conserved during a reaction even if energy is released to the surroundings by the reactants.
Energy is never conserved and can be created, destroyed or it can change forms but only in nuclear reactions.
Energy is always conserved, but can’t change forms between materials.

In the following reaction, propane + oxygen → carbon dioxide + water, heat is released to the surroundings which can be used to cook food, warm homes, or power industrial processes. Which terms correctly describe this reaction?
Combustion, energy in, endothermic
Combustion, energy out, exothermic
Combustion, energy in, exothermic

In order to increase the rate of a chemical reaction, which group of situations could be applied?
Add a catalyst, increase the temperature, decrease the surface area, decrease the concentration.
Add a catalyst, decrease the temperature, increase the surface area, increase the concentration.
Add a catalyst, increase the temperature, increase the surface area, increase the concentration.

In a chemical reaction that is said to be in equilibrium, what will happen if some of the product(s) is/are removed from the system?
The remaining product will reform reactants.
The remaining reactants will move to form additional products.
The remaining reactants will stop further progress.


Element
A
B
C
Atomic Mass (g/mol)
12.0
7.8
16.4



Given the hypothetical elements above, solve the following problem:

In the unbalanced equation, AB + C2 → AC3 + B2, what is the mole ratio between C2 and B2?

2:2
3:1
1:3
Using the same hypothetical, unbalanced equation from problem 8, what mass in grams of AC3 is produced when 17.6 g of AB reacts with unlimited C2?
36.2 g
54.4 g
61.2 g

If Cadmium - 116 were to spontaneously undergo alpha decay that released two alpha particles and 4 gamma particles, what would the resulting nuclide be?
Tin - 120
Palladium - 112
Ruthenium - 108
Ruthenium - 120

In terms of water quality set forth by the EPA and monitored by the CDC, what would be the most likely measure of acceptable limits of lead (Pb) in water intended for human consumption?
400 ppm
400 ppb
15 mg/L
15 µg/L

Which of the following locations was the site of a significant water contamination event?
Austin, TX
East Palestine, OH
Sacramento, CA

**One additional point if you can describe that event!
________________________________________________________________________________________________________________________________________________________________________________________________

Answer 1

It seems like you have a list of questions related to chemistry and physics. Here are the answers to your questions:

Radiation

Exothermic, there is a large amount of energy released to the surroundings.

It was energy put into the solid in order to make the particle reach activation energy to break apart.

Energy is always conserved, but can change forms between materials.

Combustion, energy out, exothermic

Add a catalyst, increase the temperature, increase the surface area, increase the concentration.

The remaining reactants will move to form additional products.

For question 8 and 9, I need more information about the elements A, B and C to solve them.

For question 10, if Cadmium-116 were to spontaneously undergo alpha decay that released two alpha particles and 4 gamma particles, the resulting nuclide would be Palladium-112.

For question 11, according to the EPA and monitored by the CDC, the most likely measure of acceptable limits of lead (Pb) in water intended for human consumption is 15 µg/L.

For question 12, I am not sure which location you are referring to. Can you please clarify which location you are asking about?

Answer 2

Here are the answers to your questions:

1. Radiation.

2. Exothermic, there is a large amount of energy released to the surroundings.

3. It was energy put into the solid in order to make the particle reach activation energy to break apart.

4. Energy must always be conserved during a reaction even if energy is released to the surroundings by the reactants.

5. Combustion, energy out, exothermic

6. Add a catalyst, increase the temperature, increase the surface area, increase the concentration.

7. The remaining reactants will move to form additional products.

8. 1:3

9. 54.4 g

10. Ruthenium - 108

11. 15 μg/L

12. Flint, MI

Flint experienced significant lead contamination of its municipal water supply due to the switching of its water source from Detroit's water system to the Flint River. The river water was highly corrosive and caused lead to leach from the city's aging pipes and fixtures into the water, poisoning many residents.