 # Chem Lab

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333 Words Grammar Plagiarism  Writing  Score Chem Lab Pre Lab Questions

1. What are the basic units of length, mass, volume, and temperature in the SI system?
Length= meters (m)
Volume= kilograms (kg)
Temperature= Kelvin (K)

2. What decimal power do the following abbreviations represent:
a) M=10^6
b) K=10^3
c) M=10 ^-3
d) N=10^-9
e) µ=10^-6

3. What is the number of significant figures in each of the following measured quantities?
a) 351 g  3
b) 0.0100 mL  4
c) 1.010 mL  4
d) 3.72 x 10^-3 cm 3

4. What is the length of a crystal of copper sulfate in millimeters that is 0.250 inches long?
.250 in x (1 mm/.0349 in) = 6.34mm

5. Perform the following conversions:
a) 72.3 mg x (1 g/1000 mg) = .0723 g
b) 6.0 x 10^-10 m x (1000 nm/1 m) = 6.0 x 10^-7 mm
c) 325 mm x (1 m/1000 mm) x (10^-6 µm/ 1 m) =325,000 µm

6. DNA is approximately 2.5 nm in length. If an average man is 6 feet tall, how many DNA molecules could be stacked end to end in an average man?
6 ft x (.3048 m/1 ft) x (10^9 nm/1 m) = 1.8288 x 10^9 nm
1.8288 x 10^9 nm/2.5 nm= 7.3152 x 10^8 DNA molecules 7. A liquid has a volume of 3.70 liters. What is its volume in… mL: 3.70 L x (1000 mL/1 L) = 3,700 mL cm^3: 3.70 mL x (1 cm^3/1 mL) = 3,700 cm^3
8. Why should you never weigh a hot object?
Hot objects heat the air around it. This causes molecules to heat and cool, affecting their kinetic energy. This throws off the readings of the scale. Hot objects are also more dangerous to handle and could cause damage to the scales

9. Why is it necessary to calibrate a thermometer and volumetric glass-ware?
This is necessary because all measuring instruments aren’t exactly the same and to calibrate them means to adjust their measurements of uncertainty to minimize experimental errors
10. What is precision?
Precision is how accurately measured or correct something is. It is important to be precise because it gives credibility to test results

11. What is the density of an object with a mass of 1.663 g and a volume of 0.2009

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