Sig Figs
Scientific Notation
Temp Conversion
Density
Isotopes
100
What are the rules for counting sig figs with zeros?
Leading zeros: never count it ex: 0.048
Captive zeros: fall between nonzero digits always count as sig figs. ex: 16.07
100
Why is putting a number in scientific notation useful in chemistry?
Sig figs
100
Write out the three formulas that you have to memorize for the test. Extra 50 points if you can write the other three from my SI session.
100
What is the density formula with units?
D= M/V
mass/Volume
g/cm3 or g/mL3
100
In what ways are isotopes different and the same?
different numbers of neutrons but the same number of protons and electrons
200
How many sig figs are in 299.
3
200
Write this number in scientific notation and round to 3 sig figs: 921.56
9.22*102
200
Convert 33.9°C to Fahrenheit (3 sig figs).
93.0°F
200
What is the mass of 4.00 cm3 of sodium (density = 0.97 g/cm3)?
3.88g
200
An ion with a 3+ charge contains 49 electrons. Which of the following ions is it?
a. In
b. Be
c. Al
d. Sr
In
300
How many sig figs are in 0.00000000000090?
2
300
Write this number in scientific notation and round to 3 sig figs: 89294
8.93*104
300
Convert 293K to Celsius (3 sig figs).
19.9°C
300
What is the mass of 125 mL gaseous chlorine (density = 3.16 g/L)?
0.395g
300
An ion with a 2+ charge contains 38 electrons. Which of the following ions is it?
a. Li
b. Ba
c. B
d. Sr
Sr
400
Round the following to the smallest sig fig. 71.9*1.569 = ____.
113
400
Write this number in scientific notation and round to 3 sig figs: 0.0000853
8.53*10-5
400
Convert 46°F to Kelvin (3 sig figs).
281K
400
An irregularly shaped stone was lowered into a graduated cylinder holding a volume of water equal to 2mL. The height of the water rose to 7mL/ If the mass of the stone was 25 g, what was its density?
5g/mL
7mL-2mL=5mL
25g/5mL
400
Write the symbol: the ion with a 1+ charge, atomic number 55, and mass number 133
133/55 Cs+
mass #: 133
atomic #: 55
500
Round the following to the smallest sig fig. 52.1-3.461 = _____.
48.6
500
Write this number in scientific notation and round to 3 sig figs: 739900000000
7.40*1011
500
Convert 99°C to Kelvin (3 sig figs).
372K
500
Silver has a density of 10.5 grams/cm3 and gold has a density of 19.3 g/cm3. Which would have the greater mass, 10cm3 of silver or 10cm3 of gold?
Gold
10.5g/cm3*10cm3
105g
19.3g/cm3*10cm3
193g
500
A certain isotope X3+ contains 28 protons and 50 neutrons. Identify the mass number, atomic number, and the element.
81/31 Ga3+
mass #: 81
atomic #: 31