Q: A student needs to convert $$0.00560\ \mathrm{kg} to $$milligrams. What is the correct answer in scientific notation?

$$5.60 \times 10^6$\ \mathrm{mg}$$

Question 1

Which of the following statements best describes the difference between a physical and a chemical change? Consider the example of boiling water and burning wood.

Accepted Answer

Boiling water is a physical change because the water remains H$$_2O$$, while burning wood is a chemical change because it produces new substances such as CO$$_2$$ and ash.

Question 2

A sample contains two isotopes of magnesium: 24Mg (78.99% abundance, mass = 23.985 amu) and 26Mg (21.01% abundance, mass = 25.983 amu). What is the atomic mass of magnesium? (Round to two decimal places.)

Accepted Answer

$$24.31$$ amu

Question 3

Which of the following best describes a homogeneous mixture?

Accepted Answer

A mixture in which the composition is uniform throughout, such as saltwater.

Question 4

A student measures the mass of a sample as 12.345 g using a balance that reads to the thousandths place. Which of the following measurements is recorded with the correct number of significant figures?

Accepted Answer

12.345 g

Question 5

Which of the following elements is a halogen?

Accepted Answer

Chlorine (Cl)

Question 6

A reaction releases heat to the surroundings and the energy diagram shows the products at a lower energy than the reactants. Which type of reaction is this?

Accepted Answer

Exothermic

Question 7

Which of the following is a correct application of Dalton’s atomic theory?

Accepted Answer

Atoms of the same element have identical properties, and compounds are formed by the combination of atoms in fixed ratios.

Question 8

Convert $$25.0\ ^\circ\mathrm{C} to $$Kelvin.

Accepted Answer

$$298.15\ \mathrm{K}$$

Question 9

Which of the following is a property of metals?

Accepted Answer

They are good conductors of heat and electricity.

Question 10

A laboratory accident occurs and a student spills a strong acid on their hand. What is the correct first response according to basic laboratory safety?

Accepted Answer

Rinse the affected area with plenty of water immediately.

Question 11

Which of the following elements occurs naturally as a diatomic molecule?

Accepted Answer

Oxygen (O$$_2)$$

Question 12

A sample of water is heated from $$20.0\ ^\circ\mathrm{C} to$$ $$80.0\ ^\circ\mathrm{C}. If $$the mass of water is $$50.0\ \mathrm{g}$$ and the specific heat capacity is $$4.18\ \mathrm{J}/\mathrm{g}\cdot\mathrm{K}$$, how much heat ($$q) is $$absorbed?

Accepted Answer

$$12,540\ \mathrm{J}$$

Question 13

Which of the following ions is expected for a Group 2 element?

Accepted Answer

$$\mathrm{M}^{2+}$$

Question 14

Which of the following best describes the law of conservation of mass?

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction.

Question 15

Which of the following is the correct symbol and charge for a sodium ion?

Accepted Answer

$$\mathrm{Na}^{+}$$

Question 16

A student needs to convert $$0.00560\ \mathrm{kg} to $$milligrams. What is the correct answer in scientific notation?

Accepted Answer

$$5.60 	imes 10^6$\ \mathrm{mg}$$

Question 17

Which of the following is a main-group element?

Accepted Answer

Magnesium (Mg)

Question 18

A neutral atom of chlorine has an atomic number of 17 and a mass number of 35. How many neutrons does it have?

Accepted Answer

18

Question 19

Which of the following best describes a hypothesis?

Accepted Answer

A tentative explanation that can be tested by experiments.

Question 20

Which of the following is a property of water that makes it essential for life?

Accepted Answer

It has a high specific heat capacity, allowing it to moderate temperature changes.

Introductory Chemistry Exam 1 Study Guide

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