$$5.06 \times 10$$^{2}$$ \ \mu g$$

Question 1

Which statement best describes the Law of Conservation of Mass as demonstrated in a chemical reaction?

Accepted Answer

The total mass of the reactants equals the total mass of the products.

Question 2

Which of the following is a chemical property?

Accepted Answer

The tendency of copper to turn green when exposed to air

Question 3

How many significant figures are in the measurement 0.0002080 kg?

Accepted Answer

4

Question 4

Convert 5.06 	imes $$10^{-4}$$ \ \mathrm{g} to micrograms (\mu g).

Accepted Answer

$$5.06 	imes 10$$^{2}$$ \ \mu g$$

Question 5

Which of the following best describes Rutherford’s model of the atom?

Accepted Answer

Atoms have a small, dense nucleus containing protons and neutrons, with electrons in mostly empty space around it.

Question 6

A magnesium ion has 10 electrons. What is its charge?

Accepted Answer

$$2+$$

Question 7

Which of the following compounds is insoluble in water?

Accepted Answer

CuS

Question 8

Which of the following is a redox reaction?

Accepted Answer

$$2 \mathrm{Li}(s) + \mathrm{Cl}_2(g) \rightarrow 2 \mathrm{LiCl}(s)$$

Question 9

What is the formula for the ionic compound formed from aluminum and oxygen?

Accepted Answer

$$\mathrm{Al}_2\mathrm{O}_3$$

Question 10

A sample of ethanol has a mass of 15.8 g. Given the density of ethanol is $$0.789 \ \mathrm{g/cm}^3$$, what is the volume of the sample in mL?

Accepted Answer

$$12.5 \ \mathrm{mL}$$

Question 11

Which of the following best describes a heterogeneous mixture?

Accepted Answer

A mixture in which the individual components are not evenly distributed

Question 12

Which of the following is the correct SI base unit for temperature?

Accepted Answer

Kelvin (K)

Question 13

A reaction produces 20.0 g of NH$$_3$$ when the theoretical yield is 26.0 g. What is the percent yield?

Accepted Answer

$$76.9\%$$

Question 14

Which of the following is NOT a postulate of Dalton’s Atomic Theory?

Accepted Answer

Atoms can be created and destroyed in chemical reactions.

Question 15

Which of the following best describes an endothermic reaction?

Accepted Answer

A reaction that absorbs energy from the surroundings

Question 16

What is the correct formula to calculate the amount of heat absorbed or released by a substance?

Accepted Answer

$$q = m \cdot C \cdot \Delta T$$

Question 17

Which of the following is a physical property?

Accepted Answer

The shiny appearance of silver

Question 18

Which of the following best describes a solid at the molecular level?

Accepted Answer

Atoms or molecules are close together and oscillate about fixed points

Question 19

Which of the following is the correct conversion factor for changing calories to joules?

Accepted Answer

$$1 \ \mathrm{cal} = 4.184 \ \mathrm{J}$$

CHEM 280 Midterm Review: Introduction to Chemistry Study Guide

Study Guide - Practice Questions