Mod 1- Measurement & units
What is the definition of matter?
Matter is anything that has air and takes up space.
Johnny pushes hard against the wall for 2 hours. He's exhausted. Does he do any work? Why or why not?
No, because Work = Force x Distance. The distance the wall moved was 0 so the work also = 0.
What is the chemical formula for:
a) Selenium trioxide
b) Calcium sulfide
a) SeO3
b) CaS
Classify the following as physical or chemical changes:
a) firewood burning
b) water evaporating
c) a plate breaking
d) bread molding
a) chemical
b) physical
c) physical
d) chemical
What is the atomic number for Gold?
79
1 cm3 = 1 __________
millimeter
State the First Law of Thermodynamics and then define what is it the Law is mentioning.
The First Law of Thermodynamics states that Energy cannot be created or destroyed.
Energy is the ability to do work.
State the Law of Mass Conservation and the Law of Definite Proportions.
The Law of Mass Conservation says that mass can neither be created or destroyed. It only changes form.
The Law of Definite Proportions says that the proportion of elements in any compound is always the same.
What classification of matter does each fall under?
a) banana nut bread
b) solid iron bar
c) salt water
d) distilled water
a) heterogenous mixture
b) element
c) homogenous mixture
d) compound
What is Avogadro's number (exactly) and what does it represent?
6.02 x 1023 and it represents one mole of a substance.
If the actual length of a book is 45.3 cm, which measurement is more precise and which is more accurate?
a) 45.2 cm
b) 46.3490 cm
a) is more accurate because it's close to the actual.
b) is more precise because the answer is given on a smaller scale (in this case to the ten-thousandths place)
a) Define specific heat.
b) Define specific heat.calorie (cal).
c) Numerically, what is the specific heat of water?
a) Specific heat is the amount of heat necessary to raise the temperature of 1 gram of a substance, 1 degree Celsius.
b) A calorie is the amount of heat necessary to raise the temperature of 1 gm of water, 1 degree Celsius.
c) 1.0 cal/g x deg C or 4.184 J/g x deg C
List 4 differences between metals and nonmetals.
Metals conduct electricity in water. Nonmetals do not.
Metals are malleable. Nonmetals are brittle.
Metals are located on the left side of the jagged line on the periodic table. Nonmetals are on the right side of the jagged line.
Metals are shiny. Nonmetals are dull.
If a liquid goes through a phase change in which
a) the molecules slow down and move closer together, what phase change occurred and what phase is the substance now in?
b) the molecules speed up and move further apart, what phase change occurred and what phase is the substance now in?
a) The phase change is freezing and the substance is now a solid.
b) The phase change is evaporation and the substance is now a gas.
Write a balanced chemical equation for the complete combustion of Decane (C10H22).
2C10H22 + 31O2 -> 20CO2 + 22H2O
How many and which are significant figures are in the numbers 1.00450 and 0.0060?
1.00450 has six (all of them) and 0.0060 has two (6 and the last 0).
Classify each as having either potential energy, kinetic energy, or both
a) a lump of coal
b) a ray of sunlight
c) a candle flame
d) a tornado
a) potential (is not moving, but has mass)
b) kinetic (has no mass, but is moving)
c) kinetic (has no mass, but is moving)
d) both (swirling wind of air...has mass and is moving)
List the 4 assumptions of Dalton's Atomic Theory.
1) All elements are composed of small, indivisible particles called atoms.
2) All atoms of the same element have exactly the same properties.
3) Atoms of different elements have different properties.
4) Compounds are formed when atoms are joined together. Atoms can only join together in whole-number ratios.
State the Kinetic Theory of Matter.
Molecules and atoms are in constant motion, and the higher the temperature, the greater the speed.
What are the 3 types of chemical reactions and give an example of each by writing a balanced equation for each.
1) Formation: 2H2 + O2 -> 2H2O
2) Decomposition: CO2 -> C + O2
3) Combustion: 2CH2 + 3O2 -> 2CO2 + 2H2O
Silver has a density of 10.5 g/cm3. If a silver necklace has a volume of 0.015 L, what is the mass of the bracelet?
10.5 g/cm3 = 10.5 g/mL
D= mass/volume -> D x V = mass = 10.5 g/mL x .001 L ->
mass = 10.5 g/mL x .015 L x 1000 mL/1 L = 157.5 g
There are only 2 significant digits in the volume (0.015 L) so our answer must have only 2. Therefore, convert to scientific notation.. mass = 1.6 x 102 g
How many Joules does it take to heat 10.5 kg of glass from 35 to 45 degrees Celsius given the specific heat of glass is 0.837 J/ g x deg C.
q = mc (
In making Calcium Chloride, 100.0 g of Calcium plus 100.0 g of Calcium makes Calcium Chloride plus 50 g of leftover Calcium. How much Calcium and how much Magnesium should be used in order to make 1.5 kg Calcium Chloride with no leftovers?
1 kg of each.
List all 8 of the homonuclear diatomic molecules.
N2, O2, Cl2, F2, Br2, I2, At2, H2
What is the mass of an MgCO3 molecule in kg?
1 x 24.3 amu + 12.0 amu + 3 x 16.0 amu = 84.3 amu
84.3 amu x [1.66 x 10-24 g / 1.0 amu] x [1kg/1000g] = 1.40 x 10-25kg