Question 1

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

Accepted Answer

Salt dissolved in water

Question 2

Which statement best distinguishes a physical change from a chemical change?

Accepted Answer

A physical change does not alter the chemical composition of a substance, while a chemical change does.

Question 3

A sample of gold has a mass of $$19.3\ \mathrm{g}$$ and a volume of $$1.00\ \mathrm{cm}^3. $$What is the density of gold?

Accepted Answer

$$19.3\ \mathrm{g/cm}^3$$

Question 4

Which of the following best describes the difference between accuracy and precision?

Accepted Answer

Accuracy refers to how close a measurement is to the true value, while precision refers to how close repeated measurements are to each other.

Question 5

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

Accepted Answer

$$298.2\ \mathrm{K}$$

Question 6

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 7

A radioactive isotope has a half-life of $$4$$ days. If you start with $$80\ \mathrm{mg}$$, how much remains after $$12$$ days?

Accepted Answer

$$10\ \mathrm{mg}$$

Question 8

Which of the following best describes the octet rule?

Accepted Answer

Atoms tend to gain, lose, or share electrons to achieve eight electrons in their outermost shell.

Question 9

What is the ionic charge of a magnesium ion?

Accepted Answer

$$+2$$

Question 10

Which of the following is a correct Lewis structure for a neutral oxygen atom?

Accepted Answer

Six dots around the symbol O: $$\cdot\cdot\mathrm{O}\cdot\cdot$$

Question 11

Which of the following best describes a covalent bond?

Accepted Answer

A bond formed by the sharing of electrons between two nonmetals.

Question 12

How many moles are in $$3.01 	imes 10$$^{23}$$ molecules of water?

Accepted Answer

$$0.500$$ moles

Question 13

Which of the following molecules is polar due to its shape and bond polarity?

Accepted Answer

Water, $$\mathrm{H}_2\mathrm{O}$$

Question 14

Which of the following is a correct conversion from Celsius to Fahrenheit for $$0\ ^\circ\mathrm{C}$$?

Accepted Answer

$$32\ ^\circ\mathrm{F}$$

Question 15

Which of the following best describes the difference between kinetic and potential energy?

Accepted Answer

Kinetic energy is the energy of motion, while potential energy is stored energy due to position or composition.

Question 16

A patient receives a radioactive tracer with an activity of $$8.0\ \mathrm{mCi}. If $$the half-life of the tracer is $$6$$ hours, how much activity remains after $$18$$ hours?

Accepted Answer

$$1.0\ \mathrm{mCi}$$

Question 17

Which of the following is a property of metals on the periodic table?

Accepted Answer

They are good conductors of electricity.

Question 18

Which of the following is the correct symbolic notation for an atom with $$17$$ protons, $$18$$ neutrons, and $$17$$ electrons?

Accepted Answer

$$^{35}_{17}\mathrm{Cl}$$

Question 19

Which of the following best describes radioactivity?

Accepted Answer

The spontaneous emission of energy or particles from the nucleus of an unstable atom.

GOB Chemistry Exam 1 Study Guide

Guida di studio - Domande di pratica

Study guide - Flashcard