Counting Atoms
Na2Cl3
Na=?
Cl=?
Na=2
Cl=3
Gold (Au)
Pure Substance
Compound (and molecule)
Chemical or Physical? Water freezing.
Physical
What are the products in this reaction?
A + B --> C + D
C and D
KI4
K=?
I=?
K=1
I=4
Salt and Pepper
Mixture
Hydrogen gas (H2)
Molecule
Chemical or Physical? Bubbling after mixing 2 substances together.
Chemical
What is a reactant?
The starting material in a chemical reaction
3CaNO2
Ca=?
N=?
O=?
Ca=3
N=3
O=6
Salt (NaCl)
Pure Substance
Potassium (K)
Neither
Chemical or Physical? A bag gets hot after mixing substances together.
Chemical
Does this equation show the Law of Conservation of Matter? Show how you know.
A2 + B --> A2B
Yes! Both sides are equal:
A = 2
B = 1
Mg(OH)2
Mg=?
O=?
H=?
Mg=1
O=2
H=2
Carbon Dioxide
(Pure Substance)
Krypton gas (Kr)
Neither
What is a precipitate?
When a solid is made from two liquids mixing together.
Does this equation show the Law of Conservation of Matter? Show how you know.
N2 + H2 --> NH3
NOOOOOO
N = 2 // 1
H = 2 // 3
2Al(SO4)2
Al=?
S=?
O=?
Al=2
S=4
O=16
Mixture
Glucose (C6H12O6)
Compound (and molecule)
Name 3 out of the 5 signs of a chemical reaction.
Gas forms, temperature changes, smell, color changes, precipitate forms.
Does this equation show the Law of Conservation of Matter? Show how you know.
CH4 + 2O2 --> CO2 + 2H2O
Yes! Equal numbers on each side.
C = 1
H = 4
O = 4