Introduction to Thermochemistry

An alloy of unknown composition is heated to 153°C and placed into 100.0 g of water at 25°C. If the final temperature of the water ws 36.4°C, and the alloy weighed 3.85 g, what is the specific heat of the alloy?

• 108.67 J/g•°C

• 1.23 J/g•°C

• 2.78 J/g•°C

• 8.67 J/g•°C

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How much heat is produced when 750.0 mL of water is raised from 30°C to 89°C?

• 8.289 Joules

• 160.512 Joules

• 185,142 Joules

• 185.142 Joules

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How many grams of water are needed to raise the temperature by 18°C, and using 345.0 J of energy?

• 4.58 grams

• 4.62 grams

• 4.92 grams

• 5.01 grams

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When thermal energy is added to a substance, the substance's particles move:

• More rapidly at an increased diestance from each other.

• More rapidly with less distance between each other.

• More slowly with a greater distance between each other.

• More slowly with a reduced distance between each other.

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A chemical reaction that absorbs heat from the surroundings is said to be __________ and has a __________ ΔH at constant pressure.

• endothermic; positive

• endothermic; negative

• exothermic; negative

• exothermic; positive

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What kind of graph is this?

• endothermic

• exothermic

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Heat flows from _______ to _______ objects

• cooler to warmer

• warmer to warmer

• warmer to cooler

• cooler to cooler

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Heat is measured in 

• joules

• grams

• degrees celcius

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Energy can not be created or destroyed, it can only be transferred refers to the....

• law of conservation of energy

• law of conservation of mass

• life facts

• law of conservation of chemistry

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The specific heat(c) of copper is 0.39 J/g °C. What is the temperature change(∆t) when 100 Joules of heat(Q) is added to 20 grams?

• 12.82 °C

• 24.12°C

• 351 °C

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