Scientific Notation
Significant Digits
Avogadro
The Mole
100
Convert the following number to scientific notation:
450, 000, 000
4.5 x 108
100
How many significant digits are in the following:
1.23
3
100
State Avogadro's number.
6.02x1023
100
A gold coin contains 9.51x1022 atoms of gold. What amount of moles of gold is in the coin?
0.158 mol
200
Convert the following number into scientific notation:
0.000053
5.3 x 10-5
200
True or False. If the statement is false give a true statement.
Zeros that are located to the left of a value ARE significant.
FALSE
Zeros that are located to the left of a value are NOT significant.
200
The head of a small pin contains about 8x10-3 mol of iron. How many iron atoms are in the head of the pin?
Hint: be sure to include your units in your final answer
5x1021 atoms
200
A sheet of drywall contains 1.2x1026 formula units of gypsum (calcium sulphate dehydrate), CaSO4x2H2O(s). What amount in moles of gypsum is in the sheet of drywall?
2.0x102 mol
300
Convert following into scientific notation:
3100.0 x 102
3.1000 x 105
300
How many significant figures are in the following
120 000
2
300
State whether the following statements are TRUE or FALSE. If any statement is false provide a true statement.
1) Molecules represent diatomic elements and ionic compounds
2) Atoms represent single elements
3) Formula units represent any covalent compound
1) FALSE - Molecules represent diatomic elements and covalent compounds
2) TRUE
3) FALSE- Formula units represent any ionic compound
300
If you have 2.0x102 mol of C3H8, how many atoms do you have IN TOTAL?
1.3x1027 atoms
400
Calculate the following. Be sure your answer is in scientific notation. Hint: You must also consider significant digits
(3.5 x 102)(6.45 x 1010)
2.3 x 1013
400
Calculate the answer. Use the correct number of significant digits.
14.1/5
3
400
TRUE OR FALSE:
This was Avogadro.
FALSE. This is an avocado.
400
If there are 4.28x1021 atoms of hydrogen and oxygen in a sample of water, what amount in moles of water is in the sample?
2.37x10-3 mol of water
OR 0.00237 mol of water
500
Calculate the following. Give the answer in correct scientific notation.
(1.05x10-26) / (4.2x1056)
2.5x10-83
500
Calculate the answer. Use the correct number of significant digits.
(26.1) / (0.007)
4000
OR 4x103
500
Indicate the correct type of particle (atom, molecule, or formula unit)
a) 0.156 mol Au(s)
b) 7.8 mol MgCl2(s)
c)15.2 mol H2O(l)
a) atom
b) formula unit
c) molecule
500
Glauber's salt is a common name for sodium sulphate decahydrate, Na2SO4 x 10H20(s). It is used in the manufacture of detergents. Suppose that a sample of 36.2 mol of sodium sulphate decahydrate is required.
a) What number of sodium atoms would be in the sample?
b) what number of water molecules would be in the sample?
a) 4.36x1025 atoms
b) 2.18x1026 molecules