Module 1 Problem Set Quiz
Module 1 Problem Set
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Convert the following numbers from one form to another and explain your answer.
1.) 5.38 x 10-3 = _____________
2.) 623000000. = _____________
Correct Answer
Answer
1.) 5.38 x 10-3 = negative exponent = smaller than 1, move decimal 3 places = 0.00538
2.) 623000000. = larger than 1 = positive exponent, move decimal 8 places = 6.23 X 108
Complete the following conversions and show all work. Be sure to write your answer with the correct units.
1.) 25.3 g = __________ decigrams
2.) 56 ft = __________ in
Correct Answer
Answer
1.) 25.3 g x 10 dc / 1 g = 253 dg
2.) 56 ft x 12 in / 1 ft = 672 in
1.) 85 oF = ___ oC
2.) 412 oK = ___ oF
Correct Answer
Answer
1.) 85 oF - 32 ÷ 1.8 = 29.4 oC
2.) 412 oK - 273 = 139 oC x 1.8 + 32 = 282.2 oF
Complete the following problems and show all work. Be sure to show the correct number of significant figures in each calculation and answer with the correct units.
1.) What is the volume of a sample of mercury (d = 13.6 g/ml) which weighs 1000. g?
2.) What is the density of 200. ml of bromine which weighs 620. grams?
Correct Answer
Answer
1.) 13.6 g/ml = D 1000 g = M
find V = M / D = 1000 / 13.6 = 73.5 ml
2.) 200 ml = V 620 g = M
find D = M / V = 620 g / 200 ml = 3.10 g/ml
Complete the following problems and show all work when necessary. Be sure to show the correct number of significant figures in each calculation and answer with the correct units.
How many significant figures are there in each of the following numbers?
1.) 306.2
2.) 0.0231
3.) What is the mass of a sample of lead (d = 11.35 g/ml) which has a volume of 85.0 mL?
Correct Answer
Answer
1.) 306.2 contains 4 significant figures
2.) 0.0231 contains 3 significant figures
3.) M = V x D = 85.0 mL x 11.35 g/ml = 965 g (multiplication, volume contains only 3 sig figs)
Describe each material below as an element, compound, solution or heterogeneous mixture and explain your answer.
1.) Sea water
2.) Aluminum
3.) Potassium bromide
4.) Vodka
5.) Raisin bread
Correct Answer
Answers
1. Sea water
Not on periodic table (not element)
No element names (not compound)
Appears to be one substance = SOLUTION
2. Aluminum
Is found on periodic table = ELEMENT
3. Potassium bromide
Is not on periodic table (not element)
Has two element names = COMPOUND
4. Vodka
Is not on periodic table (not element)
No element names (not compound)
Appears to be one substance = SOLUTION
5. Raisin bread
Is not on periodic table (not element)
No element names (not compound)
Appears as more than one substance (bread, raisins) = HETEROGENOUS MIXTURE
Classify the following as physical or chemical changes:
1. A pile of leaves is burned
2. Your hair is trimmed by a hairstylist
3. Flour, water, eggs, butter and sugar are combined and baked to make a cake
Correct Answer
Answer
1. A pile of leaves is burned = Chemical
2. Your hair is trimmed by a hairstylist (hair is still hair but shorter) = Physical
3. Flour, water, eggs, butter and sugar are combined (Physical) and baked to make a cake = Chemical
Name the following compounds:
1.) Fe(OH)3 ____________________
2.) MgCO3 ____________________
3.) PF5 ____________________4.) HNO2 ____________________
Correct Answer
NAMING COMPOUNDS
1.) Fe(OH)3 = Iron (III) hydroxide
2.) MgCO3= Magnesium carbonate
3.) PF5 = Phosphorus pentafluoride
4.) HNO2 = Nitrous acid
Write the formula for each of the following chemical compounds below and then explain your answer by referring to the prefixes or suffixes or showing charges that were used to determine the formula.
1.) Aluminum sulfide _______________
2.) Lead (IV) oxide _______________
3.) Calcium cyanide _______________
4.) Dinitrogen Trioxide _______________
5.) Potassium bromide _______________
Correct Answer
WRITING FORMULAS
1. Al+3 , S-2 = Al2S3
2. Pb+4 , O-2 = PbO2 (need just 2 Os to balance Pb)
3. Ca+2 , CN-1 = Ca(CN)2
4. Di-two N, Tri-three O = N2O3
5. K+1 , Br-1 = KBr
