Thermochemistry #1

What is the formula to calculate heat energy using specific heat capacity?

• Q = mcΔT

• Q = mc^T

• Q = mc/T

• Q = mc^2

Define specific heat capacity.

• Specific heat capacity is the measure of a substance's resistance to flow.

• Specific heat capacity is the rate at which a substance changes from solid to liquid.

• Specific heat capacity is the amount of heat energy required to raise the temperature of a unit mass of a substance by one degree Celsius.

• Specific heat capacity is the ability of a substance to conduct electricity.

Explain the difference between endothermic and exothermic reactions in terms of heat flow.

• Endothermic reactions absorb heat, while exothermic reactions release heat.

• Endothermic reactions release heat, while exothermic reactions absorb heat.

• Endothermic reactions do not involve heat, while exothermic reactions do.

• Endothermic reactions release energy, while exothermic reactions absorb energy.

Calculate the heat released when 100g of water cools from 80°C to 20°C. (Specific heat capacity of water = 4.18 J/g°C)

• Q = 100g * 4.18 J/g°C * 60°C = 2508 J

• Q = 50g * 4.18 J/g°C * 60°C = 1254 J

• Q = 100g * 4.18 J/g°C * 80°C = 3344 J

• Q = 100g * 4.18 J/g°C * 40°C = 1672 J

What type of reaction absorbs heat from the surroundings?

• Spontaneous

• Exothermic

• Catalytic

• Endothermic

Explain why a metal spoon feels colder than a wooden spoon when left in a hot liquid.

• Metal spoon has a higher density than wood.

• Metal spoon has a lower thermal conductivity than wood.

• Metal is a better conductor of heat than wood, so the metal spoon absorbs heat faster from the hot liquid, making it feel colder.

• Metal spoon has a higher specific heat capacity than wood.

If a reaction releases 5000 J of heat and the surroundings absorb 3000 J, what is the net heat change for the system?

• 4000 J

• 2000 J

• 1000 J

• 6000 J

Which type of energy is the energy stored in chemical bonds?

• kinetic energy

• potential energy

• chemical potential energy

• mechanical energy

A piece of candy has 200 Calories per serving. How many calories of heat will be released when it is broken down?

• 200 calories

• 200,000 calories

• 836,800 calories

• 836.8 calories

A 300 gram sample of a metal is cooled from 120 ^oC to 60 ^oC, and releases 4230 J of energy. What is the specific heat of the metal?

• 7.61 x 10⁷ J/g^oC

• 4.26 J/g^oC

• 0.47 J/g^oC

• 0.235 J/g^oC