CHM 3025 Exam 1
Determine the number of protons and electrons: K+
19 protons 18 electrons
Element, Compound, or Mixture? Silver Coin
Element
which state of matter has both a fixed volume and fixed shape? solid liquid or gas
solid
nuclear theory of the atom
theory that states in part that most of the volume of the atom is empty space
goals of alchemy
to make the elixir of life, a potion that would grant immortality.
Physical or Chemical Change? The vaporization of gasoline
Physical
What is the mass? 0.0067 mol Au
0.0067 mol x 196.97 g = 1.3 g Au
What is the mass? 0.552 mol Cu
0.552 mol x 63.55 g = 35.1 g Cu
A car has a fuel efficiency of 27 miles per gallon. What is its efficiency in kilometers per gallon.
0.6214 mi/ 1 km 27 mi\ 0.6214 mi = 43 km/ gal
What is the mass? 1 Na atom
1 atom x 1/ 6.022 x 10^ -23 atoms x 22.99 g = 3.82 x 10^ -23 g Na
Dalton's Atomic Theory
1) elements are composed of atoms. 2) atoms of same element are identical, but differ from other elements. 3) elements can mix together 4) atoms only change when mixed with other elements
What is the mass? 1.8 mol S
1.8 mol x 36.02 g = 58 g S
Rutherford's model: how many electrons? Sodium: 11 protons
11 Electrons
4.92 in. to mm
125 mm 4.92 in/1 x 25.4 mm/1 in = 125 mm
Determine the number of protons and electrons: Al^3-
13 protons 10 electrons
Write in Symbol form: iodine-131
131 I 53
Rutherford's model: how many electrons? Calcium:
20 Electrons
87 ft. to m
27 m 87 ft/1 x 12 in/ft x 1 m/39.37 in = 27 m
Write in Symbol form: phosphorous- 32
32 P 15
Write in Symbol form: sulfur-35
35 S 16
A runner runs at a pace of 8.5 minutes per mile. She wants to run 10.0 km For how long should she run?
52.8 mins 10 km / 1 x 0.6214 mi/ km = 6.214 mi 6.214 mi x 8.5 minutes= 52.8 mins
Write in Symbol form: cobalt-60
60 Co 22
Determine the number of protons and electrons: N^3-
7 protons 10 electrons
8779 yd to km
8.027 km 8779 yd/1 x 1 mi/1760 yd x 1 mi/0.6214 km = 8.027 km
Determine the number of protons and electrons: F-
9 protons 10 electrons
3.8 in. to cm
9.7 cm 3.8 in/1 x 2.54 cm/1 in = 9.7 cm
Physical or Chemical Change? The burning of natural gas on a stove
Chemical
Physical or Chemical Change? The rusting of iron
Chemical
Cu-63 has a mass of 62.939 amu and a relative abundance of 69.17% Use the atomic mass of copper to determine the mass of the second copper isotope.
Cu-63 : mass: 62.939 amu & RA: 69.17% Unknown: RA: 30.83% 63.546: Atomic Weight of Copper 63.546 = (62.939 x 69.17%) + (Y x (100%-69.17%) or (30.83%)) Y= 64.908 amu
Which Greek thinker was among the first to suggest that matter was composed of atoms?
Democrtitis
Element Compound, or Mixture? Soil
Heterogenous Mixture
Element Compound, or Mixture? Coffee
Homogenous Mixture
Element, Compound, or Mixture? Air
Homogenous Mixture
Which description best describes the field of chemistry?
The science that investigates he connection between the macroscopic world and the particles that compose it
Physical or Chemical Change? The crushing of salt
Physical
How can you find the number of protons in an atom?
Protons= Atomic Number
Scientific Notation Rules
Right: Negative Left: Postive 0.0000428 = 4.28 x 10^ -5
Volume of gold and sand: 350 mL Density of the sand: 3.0 g/cm^3 Calculate the mass of each object.
Sand: = 1.0 x 10^3 g 350 mL x 1 cm3/1 mL x 3.00g/1 cm3= 1.0 x 10^3g Gold: 6.8 x 10^3 g 350 mL x 1 cm3/1 mL x 19.32 g/1 cm3= 6.8x10^3g
A 28.4 cm^3 sample of titanium has a mass of 127.8 kg. calculate the density of titanium in g/cm^3.
The density is determined by dividing the mass by the volume: 1278 g/ 28.4 cm^3 = 4.5 g/cm^3
Which statement is best categorized as a law?
in a chemical reaction, matter is neither created nor destroyed.
which substance is a pure substance? seawater orange soda nitrogen gas air
nitrogen gas
which substance is an element? table salt water sugar oxygen
oxygen
