Chem 103 exam 1-6
M1: Exam - Requires Respondus LockDown Browser + Webcam
Question 1
Complete the two problems below:
1. Convert 55673.3 to exponential form and explain your answer.
2. Convert 7.84 x 10-3 to ordinary form and explain your answer.
Answer:
1. Convert 55673.3 = larger than 1 = positive exponent, move decimal 4 places =
5.56733 x 104
2. Convert 7.84 x 10-3 = negative exponent = smaller than 1, move decimal 3
places = 0.00784
Question 2
Complete the two problems below:
Using the following information, do the conversions shown below, showing all work:
1 ft = 12 inches 1 pound = 16 oz 1 gallon = 4 quarts
1 mile = 5280 feet 1 ton = 2000 pounds 1 quart = 2 pints
kilo (= 1000) milli (= 1/1000) centi (=
1/100) deci (= 1/10)
Answer:
1. 24.6 grams x 1 kg / 1000 g = 0.0246 kg
2. 6.3 ft x 12 in / 1 ft = 75.6 inches
Question 3
Do the conversions shown below, showing all work:
1. 328oK = ? oC
2. 76oC = ? oF
3. 135oF = ? oK
Answer:
1. 328oK - 273 = 55 oC o
K → oC (make smaller) -273
2. 76oC x 1.8 + 32 = 168.8 oF o
C → oF (make larger) x 1.8 +
32
3. 135oF - 32 ÷ 1.8 = 57.2 + 273 = 330.2 o
K o
F → oC → oK
Question 4
Be sure to show the correct number of significant figures in each calculation.
,1. Show the calculation of the density of bromine if 40.3 g occupies 12.9 ml.
2. Show the calculation of the volume of 28.6 grams of kerosene with density of
0.817 g/ml
Answer:
1. D = M / V = 40..9 = 3.12 g/ml
2. V = M / D = 28..817 = 35.0 ml
Question 5
1. 13.010 contains ? significant figures.
2. 0.041 contains ? significant figures.
3. 13.010 - 0.041 = ? (give answer to correct number of significant figures)
Answer:
1. 13.010 contains 5 significant figures.
2. 0.041 contains 2 significant figures.
3. 13.010 - 0.041 = 12.969 = 12.969 (to the thousandths place for either number)
Question 6
Classify each of the following as an element, compound, solution or heterogeneous
mixture and explain your answer.
1. Barium chloride
2. Blood
3. Boron
Answer:
1. Barium chloride - is not on periodic table (not element) - has two element names
= Compound
2. Blood - is not on periodic table (not element) - no element names (not compound)
appears to be one substance = Solution
3. Boron - is on periodic table = Element
Question 7
Classify each of the following as a chemical change or a physical change
1. Milk becomes sour
2. Leaves change color in the fall
3. Grass is mowed
Answer:
1. Milk becomes sour - the sour taste is due to a new substance being formed =
chemical change
, 2. Leaves change color in the fall - color changes usually = chemical change
3. Grass is mowed - grass is still just smaller pieces of grass = physical change
Question 8
Show the full Nuclear symbol including any + or - charge (n), the atomic number
(y), the mass number (x) and the correct element symbol (Z) for each element for
which the protons, neutrons and electrons are shown - symbol should appear as
follows: xZy +/- n
12 protons, 12 neutrons, 10 electrons
Your Answer:
12 protons = Mg12, 12 neutrons = 24 Mg12, 10 electrons = (+12 - 10 = +2) = 24Mg12+2
Question 9
Name each of the following chemical compounds. Be sure to name all acids as
acids (NOT for instance as binary compounds)
1. H2SO3
2. Ca(NO3)2
3. FeI2
Answer:
1. H2SO3 - nonbinary acid = sulfurous acid
2. Ca(NO3)2 - nonbinary ionic = calcium nitrate
3. FeI2 - binary ionic = iron (II) iodide
Question 10
Write the formula for each of the following chemical compounds explaining the
answer with appropriate charges and/or prefixes and/or suffixes.
1. Chromium (III) sulfide
2. Hydroselenic acid
3. Barium iodide
Answer:
1. Chromium (III) sulfide - ide - binary of Cr+3 and S-2 = Cr2S3
2. Hydroselenic acid - hydro = binary acid of H + Se-2 = H2Se
3. Barium iodide - ide = binary of Ba+2 and I-1 = BaI2
M2: Exam - Requires Respondus LockDown Browser + Webcam
Question 1
Show the calculation of the molecular weight for the following compounds, reporting
your answer to 2 places after the decimal.
M1: Exam - Requires Respondus LockDown Browser + Webcam
Question 1
Complete the two problems below:
1. Convert 55673.3 to exponential form and explain your answer.
2. Convert 7.84 x 10-3 to ordinary form and explain your answer.
Answer:
1. Convert 55673.3 = larger than 1 = positive exponent, move decimal 4 places =
5.56733 x 104
2. Convert 7.84 x 10-3 = negative exponent = smaller than 1, move decimal 3
places = 0.00784
Question 2
Complete the two problems below:
Using the following information, do the conversions shown below, showing all work:
1 ft = 12 inches 1 pound = 16 oz 1 gallon = 4 quarts
1 mile = 5280 feet 1 ton = 2000 pounds 1 quart = 2 pints
kilo (= 1000) milli (= 1/1000) centi (=
1/100) deci (= 1/10)
Answer:
1. 24.6 grams x 1 kg / 1000 g = 0.0246 kg
2. 6.3 ft x 12 in / 1 ft = 75.6 inches
Question 3
Do the conversions shown below, showing all work:
1. 328oK = ? oC
2. 76oC = ? oF
3. 135oF = ? oK
Answer:
1. 328oK - 273 = 55 oC o
K → oC (make smaller) -273
2. 76oC x 1.8 + 32 = 168.8 oF o
C → oF (make larger) x 1.8 +
32
3. 135oF - 32 ÷ 1.8 = 57.2 + 273 = 330.2 o
K o
F → oC → oK
Question 4
Be sure to show the correct number of significant figures in each calculation.
,1. Show the calculation of the density of bromine if 40.3 g occupies 12.9 ml.
2. Show the calculation of the volume of 28.6 grams of kerosene with density of
0.817 g/ml
Answer:
1. D = M / V = 40..9 = 3.12 g/ml
2. V = M / D = 28..817 = 35.0 ml
Question 5
1. 13.010 contains ? significant figures.
2. 0.041 contains ? significant figures.
3. 13.010 - 0.041 = ? (give answer to correct number of significant figures)
Answer:
1. 13.010 contains 5 significant figures.
2. 0.041 contains 2 significant figures.
3. 13.010 - 0.041 = 12.969 = 12.969 (to the thousandths place for either number)
Question 6
Classify each of the following as an element, compound, solution or heterogeneous
mixture and explain your answer.
1. Barium chloride
2. Blood
3. Boron
Answer:
1. Barium chloride - is not on periodic table (not element) - has two element names
= Compound
2. Blood - is not on periodic table (not element) - no element names (not compound)
appears to be one substance = Solution
3. Boron - is on periodic table = Element
Question 7
Classify each of the following as a chemical change or a physical change
1. Milk becomes sour
2. Leaves change color in the fall
3. Grass is mowed
Answer:
1. Milk becomes sour - the sour taste is due to a new substance being formed =
chemical change
, 2. Leaves change color in the fall - color changes usually = chemical change
3. Grass is mowed - grass is still just smaller pieces of grass = physical change
Question 8
Show the full Nuclear symbol including any + or - charge (n), the atomic number
(y), the mass number (x) and the correct element symbol (Z) for each element for
which the protons, neutrons and electrons are shown - symbol should appear as
follows: xZy +/- n
12 protons, 12 neutrons, 10 electrons
Your Answer:
12 protons = Mg12, 12 neutrons = 24 Mg12, 10 electrons = (+12 - 10 = +2) = 24Mg12+2
Question 9
Name each of the following chemical compounds. Be sure to name all acids as
acids (NOT for instance as binary compounds)
1. H2SO3
2. Ca(NO3)2
3. FeI2
Answer:
1. H2SO3 - nonbinary acid = sulfurous acid
2. Ca(NO3)2 - nonbinary ionic = calcium nitrate
3. FeI2 - binary ionic = iron (II) iodide
Question 10
Write the formula for each of the following chemical compounds explaining the
answer with appropriate charges and/or prefixes and/or suffixes.
1. Chromium (III) sulfide
2. Hydroselenic acid
3. Barium iodide
Answer:
1. Chromium (III) sulfide - ide - binary of Cr+3 and S-2 = Cr2S3
2. Hydroselenic acid - hydro = binary acid of H + Se-2 = H2Se
3. Barium iodide - ide = binary of Ba+2 and I-1 = BaI2
M2: Exam - Requires Respondus LockDown Browser + Webcam
Question 1
Show the calculation of the molecular weight for the following compounds, reporting
your answer to 2 places after the decimal.
