QUIZ 1: STOICHIOMETRY TO VALENCES

How many moles of Cl- ions are needed to completely combine with 0.25 mole of Mg+2 ions? 0.125 0.75 0.25 0.50 0.175

0.50

An element of group II loses two electrons in the process of a chemical combination. What is its ionic charge?

+2

If the element sulfur, S, was to lose two electrons per atom, the net ion charge of each atom would be:

+2

Using the periodic table, determine the ion charges of the following elements if valence electrons were removed or added to reach the octet. barium = iodine = potassium = aluminum =

+2 -1 +1 +3

Balance the following reaction. A coefficient of "1" is understood. Choose option "blank" for the correct answer if the coefficient is "1." ______CH3OH +_______O2 → ______CO2 + ______H2O

2 3 2 4

When the amount of oxygen is limited, carbon and oxygen react to form carbon monoxide. How many grams of CO can be formed from 35 grams of oxygen? 2C + O2 → 2CO What is the molecular mass of oxygen? __________ g/mole What is the molecular mass of carbon monoxide? ________ g/mole

32.00 28.01

When the amount of oxygen is limited, carbon and oxygen react to form carbon monoxide. How many grams of CO can be formed from 35.0 grams of oxygen? 2C + O2 → 2CO Using 32.00 g/mole as the molecular mass of oxygen and 28.01 g/mole as the molecular mass of carbon monoxide, solve the above problem.

61.3

Neutral atoms of neon (atomic number 10) have the same number of electrons as each of the following except: Na + Mg +2 0 -2 F - Ar

Ar

The mass of 1 mole of Pb atoms is 6.023 x 1023. True False

False

Neutral atoms of argon (atomic number 18) have the same number of electrons as each of the following items except: Ne Cl- Ca +2 S -2 K+

Ne

A mole of Cu atoms has the same number of atoms as a mole of He atoms. True False

True

Give the location in the periodic table of the elements that have the same number of valence electrons. all members in group 18 all members in group 2 all members within any period all members in the transition metals

all members in group 2

Give the location in the periodic table of the elements that have the same number of shells. all members within any group all members within any period all members in the transition elements all members in group VIII only

all members within any period

Balance the following reaction. A coefficient of "1" is understood. Choose option "blank" for the correct answer if the coefficient is "1." __________CS2 + __________Cl2 → _________CCl4 + _________S2Cl2

blank 3 blank blank

Using the periodic table, determine the ion charges of the following families of elements if valence electrons were removed or added to reach the octet. group I = group VI = group III =

group I = +1 group VI = -2 group III = +3

Negative ions are usually formed from: nonmetals metals

nonmetals

Based upon the location of group IV on the periodic table, the ionic charge of the elements in it should be: -3 +2 +3 +1 ±4

±4