quizzes: chp 3

How many neutrons are present in C-14?

8

How many oxygen atoms are in the formula Al2(CO3)3?

9

Which of the following statements is FALSE? a. A pure substance may either be an element or a compound. b. All of the above statements are true. c. Mixtures may be composed of two or more elements, two or more compounds, or a combination of both. d. Matter may be a pure substance or it may be a mixture. e. A mixture may be either homogeneous or heterogeneous.

All are true

Which one of the following is a main-group element? a. Ce b. Cs c. Co d. Cu

Cs

What is the correct formula for a potassium ion with 18 electrons?

K+

The ionic compound that forms between potassium and oxygen is: a. K2O2. b. K2O. c. KO. d. none of the above e. KO2.

K2O.

Which of the following elements has only 12 protons? C Zn O Mg

Mg

A specific isotope of an element is known to have 15 protons and 16 neutrons. Which symbol would properly represent this isotope?

P

Isotopes are: a. none of the above b. atoms of the same element that have the same number of neutrons. c. atoms of the same element that have different number of electrons. d. atoms of the same element that have different number of protons. e. atoms of the same element that have different number of neutrons.

atoms of the same element that have different number of neutrons.

Which of the following is a homogeneous mixture? a. molten iron b. stainless steel c. trail mix d. none of the above e. water

b. stainless steel

What is correct name of the compound whose formula is BF3?

boron trifluoride

An isotope represented as S-34: a. has 34 protons. b. must have exactly 18 electrons. c. none of the above d. contains exactly 18 neutrons. e. is an isotope of sodium.

contains exactly 18 neutrons

Which of the following items is a mixture? a. water b. none of the above c. sugar d. helium e. brass

e. brass

Which among the following elements does NOT exist as a diatomic molecule in nature? a. none of the above b. fluorine c. nitrogen d. hydrogen e. neon

e. neon

All of the following can be considered physical properties EXCEPT: a.taste. b. density. c. boiling point. d. color. e. flammability.

flammability

An atom containing 7 protons, 8 neutrons, and 7 electrons: a. is charge-neutral. b. cannot exist. c. none of the above d. is an oxygen atom. e. is an ion.

is charge-neutral.

What is the name of HNO2?

nitrous acid

How would you classify sugar? a. pure substance-element b. none of the above c. mixture-homogeneous d. mixture-heterogeneous e. pure substance compound

pure substance-compound

Which of the following items is a physical property? a. the tarnishing of a copper statue b. the odor of spearmint gum c. the corrosive action of acid rain on granite d. the combustion of gasoline e. none of the above

the odor of gum

When elements combine to form compounds: a. their properties do not change. b. none of the above c. their properties change completely. d. their properties are completely random.

their properties change completely

Physical properties are: a. those that a substance displays without changing its composition. b. identical for all solid matter. c. none of the above d. those that cause atoms and molecules to change. e. those that a substance displays only through changing its composition.

those that a substance displays without changing its composition.