Sig Figs
Dimensional Analysis
Law of Conservation
Molecular Weight
Atom/Ion
100

Calculate the following problem and round to the correct number of significant figures.

3.24 + 7.0 = ?



10.2

100

Convert 25 inches to cm (1in=2.54cm)

64 cm

100

The decomposition of 20.0 g of water (H2O)
results in 18.0 g of oxygen (O2) and 2.0 g of
hydrogen (H2). What is the oxygen-to-hydrogen mass ratio?

9:1

100

Calculate the Molecular Weight of:

CH2

14.0266 g/mol

100

Identify the Atom/Ion:

Atomic number: 52

Mass number: 128


Tellurium

200

Calculate the following problem and round to the correct number of significant figures.

3.24 x 7.0 = ?

23

200

Convert 0.53 kilograms to grams (1kg=1000g)

53000g

200

Sample 1: 15.0g of hydrogen and 12.0g oxygen

Sample 2: 2.0g of hydrogen and 32.0g of oxygen

What is the oxygen-to-hydrogen mass ratio in each of the two samples?

Sample 1: 8:1

Sample 2: 16:1

200

Calculate the Molecular Weight of:


C4H6

54.088 g/mol

200

Identify the Atom/Ion:

Mass #: 88


Strontium

300

Calculate the following problem and round to the correct number of significant figures.

713.1 - 3.872 = ?

709.2

300

Convert 5.2 miles to inches (1mi=5280 ft, 1ft=12in)

329,472 in

OR

 3.3 x 10^5 in

300

Two samples of CO2 are decomposed.

Sample 1 produces: 25.6g of oxygen and 9.60g of carbon

Sample 2 produces: 21.6g of oxygen and 8.10g of carbon

Are these results consistent with the law of definite proportions? Why?

Yes! 

mass O / mass C = 25.6g/9.60g = 2.67

mass O / mass C = 21.6g/8.10g = 2.67

300

Calculate the Molecular Weight of:

NaOH

39.997 g/mol

300

Identify the Ion AND it's charge: 

11 protons

12 neutrons

10 electrons

Sodium +1

400

Calculate the following problem and round to the correct number of significant figures.


710 / 3.0 = ?

240

400

Convert 7.58 centimeters to nanometers (1m=10^2cm, 1m=10^9nm)

7.58 x 10^7 nm

400

Nitrogen dioxide (NO2) contains 2.28g of oxygen for every 1.00g nitrogen

Nitrous Oxide (N2O) contains 0.570g of oxygen to every 1.00g nitrogen.

Is this consistent with the aw of multiple proportions? Why?

Yes!

(mass O to 1g N) / (mass N to 1g O) 

228/0.570 = 4.00

400

Calculate the Molecular Weight of:


H2SO4

98.077 g/mol

400

Identify the Ion AND charge:

13 protons

14 neutrons

10 electrons

Aluminum +3

500

Calculate the following problem and round to the correct number of significant figures.

(12.4 x 7.943) + 0.0064 = ?

98.5

500

Convert 3.44 milligram per second to kilogram per hour (1mg=10^-3g , 1kg=10^3g)

0.0124 kg/hr

OR 

1.24 x 10^-2 kg/hr

500

A 1.0g sample of hydrogen reacts completely with 19.0g of fluorine to form a compound of hydrogen and fluorine (HF). 

H+F---> HF

1) What is the percent by mass of each element in the compound? 

2) What mass of hydrogen would be present in a 40 gram sample of this compound?

1) 5% Hydrogen, 95% Fluorine

2) 0.05x40= 2.0g

500

Calculate the Molecular Weight of:

(NH4)2CO3

96.09 g/mol

500

Given Fe2+, how many electrons and neutrons does it have?

24 electrons, 30 neutrons