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Worksheetschemistry form 4 3.1-3.3
Total questions: 50
Worksheet time: 50mins
Each element is defined by the number of
Atoms
Isotopes
Neutrons
Protons
Nuclei.
What is the relative formula mass of ammonium nitrate, NH4NO3 ?
[Relative atomic mass: N, 14; H, 1; O, 16]
76
79
80
90
Calculate the relative formula mass of
copper (ii) chloride, CuCl2
[Relative atomic mass:
O = 16 ; Al = 27 ; S = 32 ; Cl = 35.5 ; Cu = 64 ]
(a)
Calculate the relative formula mass of
aluminium sulphate, Al2(SO4)3
[Relative atomic mass:
O = 16 ; Al = 27 ; S = 32 ; Cl = 35.5 ; Cu = 64 ]
(a)
What is the relative atomic mass (Ar) of Carbon?
6
12
18
7
What is the relative atomic mass (Ar) of Xenon (Xe)?
54
77
131
132
What is the relative atomic mass (Ar) of Chlorine (Cl)?
35.5
17
18.5
0.5
What is the relative molecular mass (Mr) of Hydrochloric Acid (HCl)?
18
34.5
36.5
35.1
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
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
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
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
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 Mg 2+ ions are found in 1.00 mol of MgO?
3.01 x 10 ^23
12.04 x 10 ^23
6.02 x 10 ^23
6.02 x 10 ^25
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
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
The molecular formula for a carbon and hydrogen compound is C8H18. What is the empirical formula?
C8H18
C9H4
C18H8
C4H9
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
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
Which of the following compounds is correctly matched with its empirical formula?
Dihydrogen dioxide - H2O2
Hydrogen dioxide - H2O
Tetrahydrogen dioxide - H4O2
Dihydrogen dioxide - HO
Acetone, C3H6O, is the main component of fingernail polish remover. What is the molar mass of acetone to the nearest hundredths place?
29.018 g/mol
34.058 g/mol
58.1 g/mol
58.08 g/mol
What is the percent composition of hydrogen in water?
89.8%
11.2%
66.7%
33.3%
An empirical formula is defined as _______?
The lowest whole number ratio of atoms in a formula.
The actual whole number ratio of atoms in a formula.
The formula showing the ratio of atoms in a formula.
The formula showing the ratio of moles in a formula.
Chalk is mostly made of calcium carbonate, CaCO3. If it took 48.6 g of chalk to write your name on the sidewalk, how many moles of calcium carbonate does your name contain?
0.486 mol
0.714 mol
1.40 mol
2.06 mol
Methyl acetate, is a solvent commonly used in paints, ink, and adhesives, and is often identified by the formula CH₃COOCH₃. What is the empirical formula for methyl acetate?
CH2O
C6H12O6
C3H6O2
C1.5H3O
