CHEM 280 Quiz 1
If a cube is 4.0cm on all sides, what is the volume? a. 64 cc b. 16cc c. 64cm d. 16 mL
64 cc
which of the following could be the proper measurement of a fingernail on a little finger? A. 9 cm B. 9.0cm C. 0.9cm D. 0.90cm
D: 0.90cm
What is the larger unit? Microliter (uL) or deciliter (dL)
Deciliter
What are exact numbers?
Exact counting of discrete objects, integral #s that are part of an eq'n, defined quantities
List the proper assessment (exact or measured) for each of the following in order: 5 books, 15 g, 12 inches in 1 ft, 60 lb
Exact, measured, exact, measured
T/F: 1 mL = 1 cc
True
Centi
c; 10^-2
Which of the following are exact numbers: 0.50 lbs, 17 eggs, 300 K, 3/4 mile
17 eggs, 3/4 mile
(81.9 + 15.6) / 4.7
21
Convert: 2.54 cm to in^3
(2.54)^3 = 1 in^3 -> 16.4 in^3
What is the estimated digit: 32.80
0
1 mcg = ? g
0.000001 g
1 mL = ? L
0.001 L
1 mg = ? g
0.001 g
1 dL = ? L
0.1 L
What is this measurement with the correct # of SFs?
12.34 cm
Write the conversion relationship: L and pL
1 L = 10^12 pL
Write the conversion relationship: dg and Mg
1 Mg = 10^7 dg
Write the conversion relationship: GW and TW
1 TW = 10^3 GW
Write the conversion relationship: m and hm
1 hm = 1 x 10^2 m
Write the conversion relationship: uJ and kJ
1 kJ = 10^9 uJ
Write the conversion relationship: ns and fs
1 ns = 10^6 fs
1 ms = ? s
1 x 10^-3 s
1 ug = ? g
1 x 10^-6 g
1 nm = ? m
1 x 10^-9 m
1 TL = ? L
1 x 10^12 L
1 hm = ? m
1 x 10^2 m
1 km = ? m
1 x 10^3 m
Scientific Method
1. Observations 2. Hypothesis 3. Experiments 4. Laws 5. Theories
1 kL = ? L
1000 L
1 kg = ? g
1000 g
1 g = ? mg
1000 mg
What is this measurement with the correct # of SFs?
28.5 C
How many SFs: 0.000960
3
What is this measurement with the correct # of SFs?
30.0 mL
What is the estimated digit: 2500 mL
5
What is the uncertain digit in 2500 mL?
5
(3.1 x 2.4367) - 2.34
5.2
How many SFs: 8.91500 x 10^3
6
What do we do when taking a measurement (except on electronic devices)?
Add an estimated number
How should you ALWAYS round when using a ruler?
Always write number to the hundredths place
What is the Archimedes principle?
An irregular object can be found as far as volume by water displacement
John Dalton
Atomic theory: all matter consists of tiny particles called atoms
Density equation
D = M/V
Theories (in scientific method)
Explain causes of observations/laws
Giga
G; 10^9
What is the larger unit? Milligram (mg) or hectogram (hg)
Hectogram
If a scale has markings ever 0.1 g, what decimal place do we estimate to?
Hundredths place
How many SFs are in conversion factors (AKA equivalence statements)?
Infinite
How is density related to a sample?
It is a characteristic of a sample; less than 1 will float in water, >1 will sink
What SI units are used to measure temperature?
Kelvin
SI unit for measuring force?
Kg*m/s^2
What SI units are used to measure mass?
Kilogram
What is the larger unit? Kilometer (Km) or centimeter (cm)
Kilometer
Mega
M; 10^6
Percent by mass formula
Mass of element/total mass of compound x 100
Law of Conservation of Mass
Matter is neither created nor destroyed - the mass of the products in a chemical reaction must equal the mass of the reactants; Lavoisier
Antoine Lavoisier
Measured property of mass through combustion; Law of conservation of mass
What SI units are used to measure length?
Meter
What is the larger unit? Nanosecond (ns) or picosecond (ps)
Nanosecond
What SI units are used to measure time?
Seconds
Laws (in scientific method)
Summarize results of observations (don't explain the reasoning/causation)
Tera
T; 10^12
Hypothesis (in scientific method)
Tentative interpretations of observations
If a balance measures every one gram, what decimal place do we estimate to?
Tenths place
Precision and SFs
The greater the precision of measurements, the greater number of SFs
How many SFs are in an exact number?
Unlimited
Experiments (in scientific method)
Validate/invalidate hypothesis
should ALL ruler measurements in lab, reading to the cm place, be written to the hundredths place?
Yes
SI unit for volume
cm^3
Deci
d; 10^-1
Femto
f; 10^-15
Hecto
h; 10^2
Kilo
k; 10^3
SI unit for measuring acceleration?
m/s^2
Milli
m; 10^-3
Nano
n; 10^-9
Pico
p; 10^-12
Micro
u; 10^-6