HCCS
Chemistry 1405
CHEM 1405
Name: _____________________
Exam # 1 (Chap. 2- 4)
Score:
1) How many significant digits are in the time measurement 0.0036 second?
A) 1
B) 2
C) 3
D) 4
2) How do you express 0.000 000 000 001 in exponential form.
A) 1 × 10-13
B) 1 × 10-12
12
C) 1 × 10-1
D) 1 × 10
3) Which of the following unit factors is derived from: 1 mile = 5280 feet?
A) 1 mile/1 foot
B) 1 mile/5280 feet
C) 1 foot/5280 miles
D) 5280 miles/1 foot
4) One gram of carbon contains 502,000,000,000,000,000,000,000 atoms. Express this number of carbon atoms
in scientific notation.
21
A) 5.02 × 10
B) 5.02 × 10
22
C) 5.02 × 10
23
D) 50.2 × 10
21
5) Which of the following is the basic unit of temperature in the metric system?
A) Celsius degree (°C)
B) Fahrenheit degree(°F)
C) Kelvin unit (K)
D) all of the above
6) What is the symbol for the metric unit micrometer?
A) cm
B) mm
D) μm
C) Mm
7) What is the name corresponding to the metric symbol mL?
A) megaliter
B) metroliter
C) microliter
D) milliliter
8) Convert 2.1 x 1012 meters into Gigameters.
A) 2.1 Gigameters
B) 2.1 x 109 Gigameters
C) 2.1 x 103 Gigameters
D) None of them
9) If a marathon race is 26.2 miles, what is the distance in kilometers? (Given: 1 mile = 1.61 kilometer)
A) 26.2 KM
B) 42.2KM
C) 52.2 KM
D) 61.2 KM
3
10) If the density of Silver is 10.5 g/cm , what would be the mass of Silver which has 100 cm3 volume?
A) 1000 g
B) 950 g
C) 1,150 g
D) 1,050 g
11) If a liquid freezes at 33°F, what is the freezing point on the Kelvin scale?
A) 374 K
B) 275 K
C) 224 K
D) 324 K
12) Round up the number 1.6351 to 3 significant numbers
A) 1.64
B) 1.63
C) 1.635
D) 1.6
13) Classify water, Iron and soft drink
A)
B)
C)
D)
E)
Water is compound, Iron is mixture, soft drink is an element
Water is mixture, iron is element and soft drink is compound
Water is compound, iron is an element, and soft drink is mixture
None of them
All of them
14) Identify the correct statement about mixture
A) Mixture contains only one substance
B) Mixture can be separated by physical methods
C) Mixture forms because of chemical reaction
D) Mixture cannot be separated
15) Classify Oxygen
A) It is a pure substance
B) It is an element
C) It is in gaseous state at room temperature
D) It reacts with hydrogen to give water (H2O)
E) All the above
16) What is the correct statement about K2CrO4
A) It is a mixture with 3 elements
B) It is a compound with 3 elements
C) It is an element
D) All of them
E) None of them
17) Multiply 9.8 with 3.63 and indicate the product with proper significant numbers
A) 35.6 B) 35.5
C) 36
D) 35.57
E) 35.574
18) Identify the correct electron configuration of the atom that has 40 electrons
A) 1s2 2s22p6 3s23p6 3d10 4s2 4p6 5s24d2
B) 1s2 2s22p6 3s23p6 4s2 4p6 3d10 5s24d2
C) 1s2 2s22p6 3s23p6 4s2 3d10 4p6 5s24d2
D) 1s2 2s22p6 3s23p6 4s2 3d12 4p4 5s24d2
19) How many protons would be in an element that has mass number 45 and atomic number 22?
A) 67
B) 45
C) 22
D) 23
20) Identify the maximum number of electrons in the 3rd shell of iron atom
A) 32
B) 8
C) 18
Part II: (8 points each)
1) Calculate the density of each of the following
a) 43.80g of Chromium metal has volume of 6.10 cm3
b) 29.86g of Olive oil has the volume of 32.6 mL
c) 46.5g of blood plasma with the volume of 0.0453 L
D) 2
E) 6
2) Match the following
Cobalt
Heterogeneous mixture
Sugar
Element
Soda
Homogeneous mixture
Salad
Compound
3)
Fill in the blanks
Element
Mass number
Oxygen
18
Plutonium
232
Silicon
28
Radium
184
Uranium
235
Electrons
Protons
4. Calculate the average mass of Sulfur from the following data
S-32:
S-33:
S-34:
S-36:
31.9721 amu
32.9715 amu
33.9679 amu
35.9671 amu
(95%)
(0.76%)
(4.22%)
(0.014%)
5. Write the complete and condensed electron configuration of Ruthenium.
Neutrons
Bonus question (5 points)
A piece of metal weighing 32.7g is placed in a graduated cylinder containing 48.2 mL of water. If the volume
of solid and water is 63.1 mL, what would be the density of the solid?
Answer Key
Part I- Multiple Choice
1) D
8) D
15) D
2) D
9) B
16) B
3) B
10) A
17) C
4) A
11) B
18) D
5) B
12) B
19) C
6) B
13) A
20) C
7) D
14) D
Part II- Show Your Work
1) 26.2 mi × (1.61 km/1 mi) = 42.2 km
2) V(mm3)= L (mm) × W (mm) × T( mm) => T(mm)= 0.645 mm3/(10.00 mm × 12.50 mm)= 5.0 × 10-3 mm
3) d= m/V => m= 10.5 g/cm3 × 100 cm3= 1050 g
4) (°F – 32 °F) × (100 °C/180 °F)= °C => -89.4 °C
5) Law of Conservation of Mass:
Na + Cl→ NaCl
0.230 g + 0.355 g= 0.585 g NaCl
Bonus Question:
%= (g Cu/ Total Sample) × 100%
(2.5/ 100)= g Cu/ 2.507 => 0.0627 g Cu
Zn= 2.507 g(Sample)- 0.0627 g(Cu)= 2.44 g