Thermo Review #1

If 5.0 grams of a substance cools from 35.0°C to 22.6°C and loses 23.6 joules of heat, what is the specific heat of the substance?

• 0.076 J/g°C
• 0.24 J/g°C
• 0.38 J/g°C
• 0.62 J/g°C

The same amount of heat is added to a 10-g sample of each of the following metals all at the same initial temperature. Which metal will experience the smallest temperature change? (specific heats are provided next to each metal)

• beryllium c=1.82 J/g°C
• calcium c=0.653 J/g°C
• copper c=0.385 J/g°C
• gold c=0.129 J/g°C

1 cal = 4.184 J How much energy in joules is supplied by a breakfast bar containing 170 kcal?

• 170 J
• 711 J
• 1.7x10^5 J
• 7.11x10^5 J

Before the water behind the dam is taken in through the water intake valve, what sort of useful energy does it possess?

• heat energy
• kinetic energy
• potential energy
• mass energy

The chemical equation for the oxidation of iron(II) oxide is given below. This oxidation is an exothermic reaction with an enthalpy change of 560.66 kJ. Which of the thermochemical equations can be used to represent the enthalpy change for the given reaction? Select all that apply.

• a
• b
• c
• d

The chemical equation for the oxidation of iron(II) oxide is given below. This oxidation is an exothermic reaction with an enthalpy change of 560.66 kJ. Calculate the amount of heat released when 3.8 moles of Fe₂O₃ are formed from the reaction. Answer with correct sig figs and units.

Heat is equal to the change in enthalpy

• when the temperature is constant.
• when the density is constant.
• when the specific heat is constant.
• when the pressure is constant.

In the heating curve shown here, what process occurs at D?

• heating
• melting
• freezing
• evaporation

In the heating curve shown here, identify a letter that represents the average kinetic energy increasing. (more than one possible answer but only one is required)

How much heat is required to melt 45.0 g of ice (M=18.0 g/mol, ΔHfus = 6.01 kJ/mol)?

• 270 kJ
• 7.49 kJ
• 15.0 kJ
• 0.416 kJ