Q: A sample of iron is heated from $25\ ^\circ\mathrm{C}$ to $75\ ^\circ\mathrm{C}$. If the mass of the iron is $50\ \mathrm{g}$ and the specific heat of iron is $0.452\ \mathrm{J}/\mathrm{g}\ ^\circ\mathrm{C}$, how much heat (in joules) is absorbed by the iron?

$q = 50 \times (75-25) \times 0.452 = 1130\ \mathrm{J}$

Q: A 100 g sample of water is heated from $20\ ^\circ\mathrm{C}$ to $80\ ^\circ\mathrm{C}$. The specific heat of water is $4.18\ \mathrm{J}/\mathrm{g}\ ^\circ\mathrm{C}$. How much heat is absorbed?

$q = 100 \times (80-20) \times 4.18 = 25080\ \mathrm{J}$

Q: A 25 g sample of a metal absorbs $200\ \mathrm{J}$ of heat, causing its temperature to increase from $20\ ^\circ\mathrm{C}$ to $40\ ^\circ\mathrm{C}$. What is the specific heat of the metal?

$SH = \dfrac{200}{25 \times (40-20)} = 0.4\ \mathrm{J}/\mathrm{g}\ ^\circ\mathrm{C}$

Question 1

Which of the following best describes a compound?

Accepted Answer

A substance composed of two or more different elements in a fixed ratio that can be separated into simpler substances by chemical means.

Question 2

Which of the following is an example of a heterogeneous mixture?

Accepted Answer

A chocolate chip cookie

Question 3

Which statement about elements is correct?

Accepted Answer

Elements are the fundamental building blocks that make up all matter.

Question 4

A sample of iron is heated from $25\ ^\circ\mathrm{C}$ to $75\ ^\circ\mathrm{C}$. If the mass of the iron is $50\ \mathrm{g}$ and the specific heat of iron is $0.452\ \mathrm{J}/\mathrm{g}\ ^\circ\mathrm{C}$, how much heat (in joules) is absorbed by the iron?

Accepted Answer

$q = 50 	imes (75-25) 	imes 0.452 = 1130\ \mathrm{J}$

Question 5

Which of the following is a chemical property?

Accepted Answer

Flammability

Question 6

A student dissolves sugar in water. Which type of change is this, and why?

Accepted Answer

Physical change, because the sugar and water can be separated by evaporation.

Question 7

Which of the following statements about the states of matter is correct?

Accepted Answer

Solids have a definite volume and maintain their shape regardless of the container.

Question 8

Convert a temperature of $68\ ^\circ\mathrm{F}$ to Celsius using the correct formula.

Accepted Answer

$T_\mathrm{C} = \dfrac{68 - 32}{1.8} = 20\ ^\circ\mathrm{C}$

Question 9

Which of the following best illustrates the law of conservation of energy?

Accepted Answer

A ball at the top of a hill has potential energy that is converted to kinetic energy as it rolls down.

Question 10

A 100 g sample of water is heated from $20\ ^\circ\mathrm{C}$ to $80\ ^\circ\mathrm{C}$. The specific heat of water is $4.18\ \mathrm{J}/\mathrm{g}\ ^\circ\mathrm{C}$. How much heat is absorbed?

Accepted Answer

$q = 100 	imes (80-20) 	imes 4.18 = 25080\ \mathrm{J}$

Question 11

Which of the following is a correct statement about mixtures?

Accepted Answer

Mixtures can be separated into their components by physical means.

Question 12

Which of the following is a physical property?

Accepted Answer

Boiling point

Question 13

A 25 g sample of a metal absorbs $200\ \mathrm{J}$ of heat, causing its temperature to increase from $20\ ^\circ\mathrm{C}$ to $40\ ^\circ\mathrm{C}$. What is the specific heat of the metal?

Accepted Answer

$SH = \dfrac{200}{25 	imes (40-20)} = 0.4\ \mathrm{J}/\mathrm{g}\ ^\circ\mathrm{C}$

Question 14

Which of the following is a correct conversion for nutritional Calories?

Accepted Answer

$1\ \mathrm{Cal} = 1000\ \mathrm{cal}$

Question 15

Which of the following best describes potential energy?

Accepted Answer

The energy stored due to an object's position or composition

Question 16

A sample of gold (specific heat $0.129\ \mathrm{J}/\mathrm{g}\ ^\circ\mathrm{C}$) and a sample of water (specific heat $4.18\ \mathrm{J}/\mathrm{g}\ ^\circ\mathrm{C}$) are both heated by the same amount of energy. Which will experience the greater temperature change, assuming equal masses?

Accepted Answer

The gold, because it has a lower specific heat.

Question 17

Which of the following is an example of a chemical change?

Accepted Answer

Paper burning to produce ash and gases

Question 18

A 10 g sample of a substance at $25\ ^\circ\mathrm{C}$ absorbs $420\ \mathrm{J}$ of heat and its temperature rises to $45\ ^\circ\mathrm{C}$. What is the specific heat of the substance?

Accepted Answer

$SH = \dfrac{420}{10 	imes (45-25)} = 2.1\ \mathrm{J}/\mathrm{g}\ ^\circ\mathrm{C}$

Chapter 3: Matter and Energy – Introduction to Chemistry Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards