Significant Figures
Dimensional Analysis/Moles
Random
Empirical/Molecular Formula & new stuff
100
How many significant figures are in the following number: 103000
3
100

How many feet per second is a car going if it travels a distance of 75 miles in 1.2 hours? (1 miles = 5280 ft)

92 ft/sec

100

What is an isotope?

each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons

100

What is the difference between an empirical and a molecular formula?

Empirical formula tells us the most reduced ratio of elements in a compound while the molecular formula tells us how many atoms of each element are in a compound

200
Calculate the following problem and give your answer with the proper significant figures: (103 X 2.2)
230
200

How many moles are in 28.0 g of C?

2.33

200

Why was Rutherford's gold foil experiment important?

He discovered that atoms had a positively charged center, known as the nucleus, leading to nuclear theory.

200

What is the formula for potassium sulfide?

K2S

300
Calculate the following problem and give your answer with the proper significant figures: 1.5*10^2 + 4.2*10^7
4.2*10^7
300

Calculate the amount the amount of moles and g that are in 1.2044 x 10^24 Atoms F. (use 18.99 g for the molar mass of F)

2.000 moles; 37.98 grams

300

What is the "plum pudding model" and who proposed it?

JJ Thompson proposed that atoms are made of positive and negatively charged particles.

300

When they are by themselves, Do the following elements exist as a molecule (diatomic), or as a single element? Na, N, F, O, Mg, K, H

Na, Mg, K: single element; N2, F2, O2, H2: diatomic elements

400
(3.4/0.8) + (3.0 X 1.45)
9
400

A fence is 1,050. square yards. Each gallon of paint will cover 901.5 square meters of area. Unfortunately, the store ran out of gallons and is only selling paint by the liter. How many liters of paints will be needed to cover the whole fence in two coats of paint? (1 gallon = 3.785 L) (1 m = 3.280 ft)

7.376 L

400

Determine the mass (in g) of 2.5 cups of water if the density of water is 1 g/cm3 and 1 cup = 240 mL

6.0 * 10^2 g

400

Name the following compound: TiCl3 * 6H20

Titanium (III) Chloride hexahydrate

500

There are 20 people in a room, each at their own computer. Each person can type 120 words per minute. How many total words will the group type in 2.543 hours? Give your answer to 4 significant figures. 

366200 words

500

How much does 7.25 * 10^25 atoms of Ca weigh? (give your answer in kg) (molecular mass of Ca = 40.08 amu)

4.83 kg

500

What is the molecular formula for a compound with an empirical formula of C2OH4 and a molar mass of 88 grams per mole?

C402H8

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