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WorksheetsYear 10 Chemistry 1 CDSS
Total questions: 155
Worksheet time: 7hrs 50mins
What is the mass of 6.02 x 1023 platinum atoms? Round to the nearest hundredths place.
30.97 g
106.42 g
140.91 g
195.09 g
If one Monster energy drink contains 0.16 g of caffeine, how many moles of caffeine do we consume when we drink 1 can? The chemical formula for caffeine is C8H10N4O2.
194.19 moles
1.07 moles
0.00082 moles
1213.69 moles
How many grams are in 1.2 x 1024 molecules of CO? (molar mass of CO = 28 g/mol)
28.2 g
55.8 g
6.02 g
1.2 g
Ga2(SO3)3
What is the volume of 5 moles of oxygen gas?
112 L
22.4 L
120 L
24 L
Which volume will be occupied by a gas containing 6.02 x 1023 atoms of He?
1.0 L
24 L
22.4 L
44.8 L
Class :
Nomer Absen :
How many moles are 98.3 grams of aluminum hydroxide, Al(OH)3? (Atomic mass of Al = 27, H= 1, O = 16)
1.26 moles
0.8 moles
7,673.4 moles
150 moles
How many atoms are contained in 25 g of NaBr? (Atomic mass of Na = 23, Br = 35)
102.96 molecules
0.24 molecules
1.45x1023 molecules
2.34 x 1020molecules
Identify the number of Chlorine atoms in 65.8 g CaCl2.
7.14 x 1023 atoms
8.71 x 1023 atoms
1.22 x 1023 atoms
3.57 x 1023 atoms
How many moles are 98.3 grams of aluminum hydroxide, Al(OH)3? (Ar Al=27, H=1, O=16)
1.26 moles
0.8 moles
7,673.4 moles
150 moles
How many grams are in 1.2 x 1024 molecules of CO? (molar mass of CO = 28 g/mol)
28.2 g
55.8 g
6.02 g
1.2 g
How many grams of silicon (atomic mass = 28.1 amu) would there be in a sample that contained 9.99 x 1022 atoms?
1.69 g
4.66 g
1.66 g
1.79 g
A student needs 65.0 g of copper(II) chloride for an experiment. How many atoms of copper is this?
2.91 x 10^23 atoms
3.91 x 10^25 atoms
2.35 x 10^23 atoms
4.70 x 10^23 atoms
6.02 x 1023 _____.
How many molecules are in 2.00 moles of H2O?
124x1024 molecules of H2O
1.20x1023 molecules of H2O
12.04 x1023 molecules H2O
124
Two moles is equal to 12.04 x 1023 atoms. But, what proper form will your calculator display it as?
1.204 x 1024
1.204 x 1022
12.04
0.1204 x 1024
An Avogadro's number of water molecules is equal to all EXCEPT _________.
1 mole of water molecules
2 moles of Hydrogen atoms and 1 mole of oxygen atoms
18 grams of water
18 molecules of water
88.0 grams of CO2 is about _____________. [Select 2 answers.]
1 mole of CO2
2 moles of CO2
6.02 x 1023 molecules of CO2
two times 6.02 x 1023 molecules of CO2
What is the molar mass of NaCl?
58 g/mol
28 g/mol
12 g/mol
6.02 x 1023
The molar mass of an element is the mass of one ____ of the element, with numbers taken from the mass number on the periodic table.
atom
molecule
mole
gram
Which of these has the greatest volume at the same temperature & pressure?
1 mole CO2 gas
1 mole of N2O4 gas
1 mole of C3H8 gas
They all have the same volume
If you have 2 grams of helium gas at standard temperature & pressure, then you DON'T have
6.02 x 1023 atoms of helium
3.01 x 1023 atoms of helium
a 1/2 mole helium
11.2 L of helium
Which of the following statements regarding the mole is incorrect?
A mole is a counting unit equal to 6.02 x 1023 particles.
The number of particles in a mole is known as Avogadro’s number.
A mole of particles of an element is numerically equal to the atomic mass of the element.
none of the above
What name is given to the number of atoms in a mole of an element?
Planck's constant
Avogadro's constant
Newtonian constant
How many moles are there in 9 g of water?
2
1
0.5
Which of the following statements regarding the mole is incorrect?
A mole is a counting unit equal to 6.02 x 1023 particles.
The number of particles in a mole is known as Avogadro’s number.
A mole of particles of an element is numerically equal to the atomic mass of the element.
none of the above
State the type of mass you will obtain from the substance H2O.
(a)
State the type of mass you will obtain from the substance Si.
(a)
Compute for the mass of H2O.
(a)
What name is given to the number of atoms in a mole of an element?
Planck's constant
Avogadro's constant
Newtonian constant
How many moles are there in 9 g of water?
2
1
0.5
A mole can be represented by the (SELECT ALL CORRECT ANSWERS)
22.4 liters of a gas at STP
The amount of molecules or atoms in a substance
Molar mass found on the periodic table of elements
The amount of fission or fusion decay over time
6.02 x 1023 _____.
A mole of potassium chloride, an ionic compound, contains 6.02 x 1023 _____.
atoms
formula units
ions
molecules
How many molecules are in 2.00 moles of H2O?
124x1024 molecules of H2O
1.20x1023 molecules of H2O
12.04 x1023 molecules H2O
124
Two moles is equal to 12.04 x 1023 atoms. But, what proper form will your calculator display it as?
1.204 x 1024
1.204 x 1022
12.04
0.1204 x 1024
When entering scientific notation numbers on your calculator you don't type in "x10". Instead you enter ____ and then the exponent
EE
EXP
Either EE or EXP depending on your brand of calculator
An Avogadro's number of water molecules is equal to all EXCEPT _________.
1 mole of water molecules
2 moles of Hydrogen atoms and 1 mole of oxygen atoms
18 grams of water
18 molecules of water
88.0 grams of CO2 is about _____________. [Select 2 answers.]
1 mole of CO2
2 moles of CO2
6.02 x 1023 molecules of CO2
two times 6.02 x 1023 molecules of CO2
What is the molar mass of NaCl?
58 g/mol
28 g/mol
12 g/mol
6.02 x 1023
Which one has the most molecules or formula units?
1 mole H2O
1 mole Al(OH)3
1 mole NaCl
They are all the same
What is the molar mass of one molecule of Nitrogen N2?
14 amu (atomic mass units)
14 g
28 g
28 amu
The molar mass of an element is the mass of one ____ of the element, with numbers taken from the mass number on the periodic table.
atom
molecule
mole
gram
Formula masses & "formula units" are used when referring to ____ and molecular masses & "molecules" are used when referring to _______.
ionic compounds ... covalently-bonded compounds
covalently-bonded compounds .... ionic compounds
atoms .... ionic compounds
covalently-bonded compounds ... atoms
Which of these has the greatest volume at the same temperature & pressure?
1 mole CO2 gas
1 mole of N2O4 gas
1 mole of C3H8 gas
They all have the same volume
If you have 2 grams of helium gas at standard temperature & pressure, then you DON'T have
6.02 x 1023 atoms of helium
3.01 x 1023 atoms of helium
a 1/2 mole helium
11.2 L of helium
True or False -- If two substances have the same number of particles, they ALWAYS have the same mass.
True
False
True or False --
If two substances have the same number of moles, they ALWAYS have the same mass.
True
False
True or False --
If two substances have the same number of particles, they ALWAYS have the same number of moles.
True
False
Which represents more particles -- 1 mole of H2O or 1 g of H2O?
1 mole
1 g
they are the same
Which represents a greater mass - 1 mole of NaCl or 6.02 × 1023 formula units of NaCl?
1 mole
6.02 × 1023 formula units
they are the same
Which has a greater mass - 5 moles of water or 5 moles of table salt (NaCl)?
water
NaCl
they are the same
Which represents a greater mass -- 1 mole of H2O or 1 g of H2O?
1 mole
1 g
they are the same
What mass of copper would have the same number of atoms as 26.98 grams of aluminum?
26.98 g
63.55 g
no way to know
Which has more particles -- 26.98 g of Al or 18.02 g of H2O?
26.98 g Al
18.02 g H2O
they are the same
Which has a greater mass - 5 atoms of iron (Fe) or 5 moles of iron (Fe)?
5 atoms
5 moles
they are the same
What is the percent by mass of magnesium in MgO?
20%
40%
50%
60%
Find the percent composition of Cu2S?
%Cu= 67.987 %S= 32.013
%Cu= 79.854 %S= 20.145
%Cu= 35.946 %S= 64.054
How many percent of chlorine is present in chloroform?
10.06%
0.84%
89.09%
99.99%
What is the percent composition of benzene, C6H6?
C = 50.%
H = 50.%
C = 85.7 %
H = 14.3%
C = 92.2%
H = 7.8%
C = 71.9%
H = 28.1%
The mass % of aluminum in aluminum sulfate is:
35.94%
15.77%
45.70 %
21.93 %
What is the general formula for the computation of percentage composition of the given element?
% mass of element = mass of element in the compound divided by mass of the compound times 100
% mass of element = mass of element in the compound divided by mass of the compound
% mass of element = mass of element in the compound divided by 100
% mass of element = mass of element in the compound
Sodium chloride is a common salt and has vast variety of applications. The molecular formula of sodium chloride is NaCl. The molar mass of NaCl is MNaCl = 22.99 + 35.45 = 58.44 g mol−1. What percent constitute sodium(Na) in a sodium chloride ions?
39. 34%
49.35%
50%
63.15%
Percentage composition of a compound tells you the percentage of the mass made up by each element in a compound.
TRUE
FALSE
When reacting Na with Cl2, we calculated that the theoretical yield should be 13 grams. Our actual yield was 12.5 grams. What is the percent yield?
90.4%
104%
96.15%
1.04%
24 grams of CH4 was added to the above reaction. Calculate the theoretical yield of CO2.
When reacting Na with Cl2, we calculated that the theoretical yield should be 13 grams. Our actual yield was 12.5 grams. What is the percent yield?
90.4%
104%
96.15%
1.04%
2Fe2O3 + C → Fe + 3CO2
You add 28 grams of carbon. You find the actual yield to be 181.2 grams of CO2. What is the percent yield of CO2? (Hint: calculate theoretical yield of CO2 first)
58.83%
308%
6435%
15.5
The reaction of 75.0g P4 with excess chlorine gas produces 110g PCl3 in lab. Find the theoretical yield and calculate percent yield for the reaction.
The reaction of 25.0 g benzene, C6H6, with excess HNO3 resulted in 21.4 g C6H5NO2. What is the percentage yield?
C6H6 + HNO3 → C6H5NO2 + H2O
100%
27.39%
54.29%
85.62%
2Pb(NO3)2 (s)→2PbO(s)+4NO2(g)+O2(g)
Percent yield can never be greater than ________.
theoretical yield
100%
both a and b
50%
4NH3 + 5O2 --> 4NO + 6H2O
If 1.21 g of NO are formed when 6.30 g of ammonia react with 1.80 g of oxygen, what is the % yield?
37.0 %
45.1 %
89.6%
10.9 %
When reacting Na with Cl2, we calculated that the theoretical yield should be 13 grams. Our actual yield was 12.5 grams. What is the percent yield?
90.4%
104%
96.15%
1.04%
Actual yield = 62g
Calculate the percent yield.
CaC₂(s) + H₂O(l) --> C₂H₂(g) + Ca(OH)₂(aq)
Fe2O3(s) + 3H2(g) → 2Fe(s) + 3H2O(l)
How many moles of iron can be made from 6 moles H2?
How many moles of water can be produced if 8 moles H2 are used?
Actual yield = 62g
Calculate the percent yield.
Reactant and products might adhere to containers causing actual yield to be less than theoretical yield.
true
false
Competing reactions might occur forming other products causing your actual yield to be less than your theoretical yield.
true
false
Some product can be transformed completely into energy causing your actual yield to be less than your theoretical yield.
true
false
Some product may be lost during filtering causing your actual yield to be less than your theoretical yield.
true
false
How many moles of hydrogen are needed to react with 2 moles of nitrogen?
Percent yield=(________)÷(________)×100%
In the image, which reactant is limiting?
The white molecules, because there are extra.
The black atoms, because they are completely used up.
The white molecules, because they are completely used up.
The black atoms, because there are extra.
How many molecules of water are there per unit of aluminum hydroxide in Al(OH)3.3H2O?
1
2
3
There is not enough information to know
How many molecules of water are there per unit of aluminum hydroxide in Al(OH)3.3H2O?
1
2
3
There is not enough information to know
What name is given to a crystal that does not contain any water of crystallization?
Dry
Hydrated
Insoluble
Anhydrous
What name is given to a crystal that contains water of crystallization?
Wet
Hydrated
Soluble
Aqueous
What is the correct chemical formula for a compound of zinc sulfate containing 7 moles of water of crystallisation?
ZnSO4.7H2O
ZnSO4 + 7H2O
ZnSO4 : 7H2O
ZnSO4(7H2O)
Which of the following statements best defines water of crystallization?
The arrangement of water molecules around an ion.
The amount of increase in size of a crystal when added to water.
Molecules of water that are present in the lattice of a crystal.
The minimum amount of water needed to completely dissolve a crystal.
In an experiment, 10 g of red CoCl2·6H2O is heated in a crucible. After a while, the sample turns violet, and a mass of 6.97 g is recorded. Further heating produces a blue powder of anhydrous CoCl2 and a constant mass of 5.46 g is recorded. Which of the following statements may explain why the sample initially turns violet?
During heating, only some of the hydrated water molecules are removed, producing a different hydrated compound but with fewer water molecules.
During heating, CoCl2·6H2O reacts with oxygen in the air to produce CoO, which is a violet solid.
During heating, there is an increase in the number of hydrated water molecules, producing a different hydrated compound but with more water molecules.
Until the sample is heated to constant mass and only the blue CoCl2 remains there is a mixture of both the blue and red forms, which appears a violet colour.
When reacting Na with Cl2, we calculated that the theoretical yield should be 13 grams. Our actual yield was 12.5 grams. What is the percentage yield?
90.4%
104%
96.15%
1.04%
In a lab, a scientist calculate he should produce 12.3 grams of product in his experiment. When he is finished collecting his product it weighs 10.1 grams. What is his percentage yield?
82%
0.82%
10.1 %
100%
The amount of product that actually forms when a chemical reaction is carried out in a laboratory is called the _________ yield.
actual
theoretical
percentage
average
CH4 + 2O2 → CO2 + 2H2O
24 grams of CH4 was added to the above reaction. Calculate the theoretical yield of CO2.
66 grams
132 grams
33 grams
8.72 grams
P4 + 6Cl2 --> 4PCl3
The reaction of 75.0g P4 with excess chlorine gas produce 110g PCl3 in the lab. Find the theoretical yield and calculate percentage yield for the reaction.
78%
64%
27%
33%
The reaction of 25.0 g benzene, C6H6, with excess HNO3 resulted in 21.4 g C6H5NO2 experimentally. What is the percentage yield?
C6H6 + HNO3 → C6H5NO2 + H2O
100%
27.39%
54.29%
85.62%
Lead nitrate can be decomposed by heating. What is the percentage yield of the decomposition reaction if 7.4g Pb(NO3)2 are heated to give an actual yield of 4.1 g PbO?
2Pb(NO3)2 (s)→2PbO(s)+4NO2(g)+O2(g)
82%
44%
56%
67%
4NH3 + 5O2 --> 4NO + 6H2O
If 1.21 g of NO are formed when 6.30 g of ammonia react with 1.80 g of oxygen, what is the % yield?
37.0 %
45.1 %
89.6%
10.9 %
Calcium carbonate reacts with hydrochloric acid to form calcium chloride, carbon-dioxide and water.
CaCO3 + 2HCl --> CaCl2 + CO2 + H2O
A contaminated sample (234g) of calcium carbonate were added to hydrochloric acid to form 48dm3 of carbon-dioxide.
What is the percentage purity of the calcium carbonate?
20.5%
42.7%
8.54%
85.4%
Sulfur undergoes oxidation to form sulfur-dioxide.
S + O2 --> SO2
An impure sample of sulfur weighing 50.0g is collected and analysed for its purity. The sample was burned in excess oxygen to form 36dm3 of sulfur-dioxide.
Calculate the percentage purity of sulfur.
48%
96%
72%
75%
H2 + O2 --> H2O
H2 + O --> H2O
