Core Chemistry
Quiz 1, 20012, July 12
Name___________________KEY_______ ID ____________________________
(1) True or false:
(a)
1.00 x 104 has 3 significant figures
T
F
(b)
All atoms contain the same number of neutrons
as protons
T
F
(c)
C and N are isotopes
T
F
(d)
Scientific theories never change
T
F
An atom can have three 1s electrons
T
F
(f)
Ions are positively or negatively charged
T
F
(g)
Different elements absorb light at different
wavelengths (colors).
T
F
(h)
Isotopes have equal numbers of protons
T
F
(I)
Ions have equal numbers of protons and lectrons
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F
(e)
(2) Smaller – the same – or larger (circle the correct sign):
(a)
Mass of an electron
<=>
Mass of a proton
(b)
Charge of an proton
Charge of a neutron
(c)
Mass of a neutron
(d)
1 mole
<=>
<=>
<=>
Mass of a proton
1 dozen
(3) 18 cc of liquid water contains how many molecules?
(a) 1 mole
(b) 6.022 x 1023
(c) Avogadro’s number
(d) all of the above
(e) none of the above
1
(4) 1 mole of N2 and 3 moles of H2 react completely with each other to form 2 moles of a
new molecule. What is the formula of that product?
(a) NH
(b) N2H2
(c) N3H
(d) NH3
(e) none of the above
(5) Consider the reaction 2H2 + O2  2H2O. If 1000 moles of H2 reacts with 1 mole of O2,
how much H2O (molar mass 18 g/mole) is formed?
(a) 18 g
(b) 32 g
(c) 36 g
(d) 1000 g
(e) 200 g
(6) Consider the results from a dart game above. Which are accurate?
(a) 1 and 2
(b) 1 only
(c) 3 and 4
(d) 2 only
(e) none of the above
(7) Light may be described as…
(a) a wave
(b) a beam of photons
(c) a laser
(d) both (a) and (b)
(e) all of the above
2
(8) If the world population was 6,775,247,739 people. How could we give this number
with 4 significant figures?
(a) 6775. million
(b) 6.775 x 109
(c) 6.775 billion
(d) all of the above
(9) On the far-way planet Kimchi there are two unusual elements X and Y.
Some of their properties are given below.
Complete the table:
protons
neutrons
electrons
molar mass
X
7
3
7
10
Y
9
11
9
20
Bonus question:
On the planet Kimchi there is a compound with an empirical formula XY and a molar
mass of 90. What is the molecular formula?
(a) XY
(b) XY3
(c) X3Y
(d) X3Y3
(e) X9Y9
3
4