Chem Math
A digital balance reads: 0.0030 grams.
How many significant digits?
2
Which element has the atomic number 27?
Co - Cobalt
What is the charge for a Bromine ion?
- 1
Draw a Lewis structure for Chlorine
Cl with 7 dots
Which state of matter has lowest kinetic energy?
Solid
What is the density of a metal sample with volume: 250 mL and mass 500 g
d = m/V
d = 500g/ 250 mL = 2g/mL
Argon has how many neutrons?
40 - 18 = 22
Most atoms want how many valence electrons?
8 - octet rule
2 - duet rule for Hydrogen and Helium
Draw a Bohr model for Boron
P = 5
E = 5
N = 11 - 5 = 6
Which physical property can be calculated by dividing mass by volume
density
5.2 x 10-4 in standard form is?
0.00052
What's the mass of an atom made of?
Neutrons plus protons
Covalent bonds form when electrons do what...
share electrons
Draw a model of particles in a GAS
circles far apart, randomly spaced, movement lines
Which type of chemical reaction is this:
A + B -> AB
synthesis
What is the molar mass of H2O?
H = 2 x 1 = 2
O = 1 x 16 = 16
Sum is 18
Groups on the periodic table have this in common
valence electrons
Name this formula:
BeF2
Beryllium Fluoride
Draw a Lewis structure for NaCl
Na +1 [Cl ]-1
Balance the following:
_ Al + _ O2 -> _ Al2O3
4Al + 3O2 -> 2Al2O3
375 mg = _ g?
0.375g
Periods on the periodic table tell us what?
Number of orbitals/ shells
Name this formula
CS2
Carbon disulfide
Draw a Lewis Dot structure for CO2
O=C=O
two lone pairs on each O
Which "Law" says matter cannot be created or destroyed?
Law of conservation of mass