Post Test ~ Science

0/1 Question 13 In the reaction H2S + 2O2→ H2SO4, the law of definite proportions predicts that for every mole of H2S you will need how many moles of O2? a. 2 mol b. 1 mol c. 3 mol d. 4 mol e. I have no clue

a. 2 mol

1/1 Question 17 A change in the color of a solution is a sign that a. a chemical change is taking place. b. a physical change has just occurred. c. I have no clue d. organic chemicals are present. e. oxygen is present.

a. a chemical change is taking place.

0/1 Question 19 A substance that undergoes a change in a chemical reaction is a. a reactant. b. an enzyme. c. a product. d. a chemical. e. I have no clue

a. a reactant.

1/1 Question 4 A chemical equation is balanced by changing or adding a. coefficients. b. chemical symbols. c. subscripts. d. reactants. e. I have no clue

a. coefficients.

0/1 Question 20 Which of the following elements is an alkali metal? a. sodium b. magnesium c. mercury d. calcium e. I have no clue

a. sodium

Question 1 Atoms of elements that are in the same group have the same number of a. valence electrons. b. protons. c. protons and neutrons. d. I have no clue e. neutrons.

a. valence electrons.

1/1 Question 23 The charge of an electron is a. +1. b. -1. c. 0. d. -2. e. I have no clue

b. -1.

1/1 Question 11 Each molecule of table sugar, C12H22O11, contains a. 6 atoms of carbon. b. 12 atoms of carbon. c. I have no clue d. 0 atoms of carbon. e. 1 atom of carbon.

b. 12 atoms of carbon.

0/1 Question 2 When copper combines with oxygen to form copper (II) oxide, the charge of the copper ion is a. Cu3+. b. Cu2+. c. I have no clue d. Cu1+. e. Cu4+.

b. Cu2+.

0/1 Question 22 Which statement about the atomic nucleus is correct? a. The nucleus is made of electrons and has a positive charge. b. The nucleus is made of protons and neutrons and has a positive charge. c. The nucleus is made of electrons and has a negative charge. d. I have no clue e. The nucleus is made of protons and neutrons and has a negative charge.

b. The nucleus is made of protons and neutrons and has a positive charge.

0/1 Question 12 In which type of bond do atoms share electrons? a. metallic bonds b. covalent bonds c. ionic bonds d. polyatomic bonds e. I have no clue

b. covalent bonds

0/1 Question 7 An atom's mass number equals the number of a. protons. b. protons plus the number of neutrons. c. protons plus the number of electrons. d. I have no clue e. neutrons.

b. protons plus the number of neutrons.

0/1 Question 15 Dalton's atomic theory stated that every element was made of atoms that could not be subdivided, atoms of the same element are alike, and a. atoms are constantly in motion. b. the nucleus is the center of the atom. c. atoms can join to form molecules. d. I have no clue e. atoms are made of protons, neutrons, and electrons.

c. atoms can join to form molecules.

0/1 Question 10 The forces that hold different atoms or ions together are a. electric currents. b. I have no clue c. chemical bonds. d. nuclear forces. e. physical bonds.

c. chemical bonds.

1/1 Question 9 Valence electrons determine an atom's a. I have no clue b. period. c. chemical properties. d. mass. e. electric charge.

c. chemical properties.

0/1 Question 5 The name for the compound with the formula Cr2O3 would be written as a. chromium(II) oxide. b. chromium(I) oxide. c. chromium(III) oxide. d. chromium oxygen. e. I have no clue

c. chromium(III) oxide.

0/1 Question 3 According to modern atomic theory, it is nearly impossible to determine an electron's exact a. charge b. I have no clue c. position. d. color. e. mass.

c. position.

0/1 Question 25 Group 18 noble gases are inert because a. they can have either a positive or a negative charge. b. their outermost energy level is missing one electron. c. their outermost energy level is full. d. I have no clue e. they readily form positive ions.

c. their outermost energy level is full.

0/1 Question 21 In a balanced chemical reaction, the total mass of the products always equals the a. I have no clue b. proportional masses of the reactants. c. total mass of the reactants. d. atomic mass of the reactants. e. molar mass of the reactants.

c. total mass of the reactants.

0/1 Question 30 In the reaction 2H2O → 2H2 + O2, if you start with 2 mol of water, how many moles of hydrogen gas are produced? a. 1 mol b. 3 mol c. 4 mol d. 2 mol e. I have no clue

d. 2 mol

0/1 Question 27 The name for the compound with the formula CuBr2 would be written as a. copper bromine. b. I have no clue c. copper(I) bromide. d. copper(II) bromide. e. copper(III) bromide.

d. copper(II) bromide.

0/1 Question 18 Oxygen's atomic number is 8. This means that an oxygen atom has a. a total of eight protons and neutrons. b. eight neutrons in its nucleus. c. I have no clue d. eight protons in its nucleus. e. a total of eight neutrons and electrons.

d. eight protons in its nucleus.

0/1 Question 8 An ionic bond is a bond that forms between a. the electrons of two different atoms. b. one atom's nucleus and another atom's electrons. c. atoms with neutral charges. d. ions with opposite charges. e. I have no clue

d. ions with opposite charges.

0/1 Question 14 The anion formed from an oxygen atom is called a(n) a. nitrous oxide. b. I have no clue c. carbon dioxide. d. oxide ion. e. oxygen ion.

d. oxide ion.

0/1 Question 26 In which substance do the molecules have the strongest attractions to one another? a. sulfuric acid, a liquid b. hydrogen, a gas c. I have no clue d. sugar, a solid e. water, a liquid

d. sugar, a solid

1/1 Question 29 What happens in a chemical reaction? a. Atoms are created. b. Molecules are created. c. I have no clue d. Atoms are destroyed. e. Atoms are rearranged.

e. Atoms are rearranged.

0/1 Question 28 Often atoms join so that each atom will have a. I have no clue b. more electrons than either protons or neutrons. c. an equal number of protons and electrons. d. an even number of electrons. e. an outermost energy level that is full of electrons.

e. an outermost energy level that is full of electrons.

1/1 Question 16 Most halogens form compounds by a. joining with both calcium and carbon. b. I have no clue c. losing protons. d. losing an electron to form a positive ion. e. gaining an electron to form a negative ion.

e. gaining an electron to form a negative ion.

1/1 Question 6 Atoms have no electric charge because they a. I have no clue b. have neutrons in their nuclei. c. have an equal number of charged and noncharged particles. d. have an equal number of neutrons and protons. e. have an equal number of electrons and protons.

e. have an equal number of electrons and protons.

0/1 Question 24 The name dinitrogen tetroxide tells you that this compound contains a. two nitrogen atoms and two oxygen atoms. b. I have no clue c. four nitrogen atoms and two oxygen atoms. d. four nitrogen atoms and four oxygen atoms. e. two nitrogen atoms and four oxygen atoms.

e. two nitrogen atoms and four oxygen atoms.