Vocabulary
The total mass before a chemical reaction is the same as the total mass after a chemical reaction
Law of Conservation of Mass
What symbol does the element Sulfur have?
S
A student calculated the volume of a cube to be 2 cm3 and the mass to be 14 grams. Calculate the density.
Density = Mass / Volume
Density = 14 g / 2 cm3 = 7 g/cm3
A new substance formed when 2 liquids were mixed together. What kind of change occurred?
Chemical change
In a chemical equation, ____________ are on the left of the arrow and ____________ are on the right of the arrow.
Reactants, products
A substance made from two or more different elements that have been chemically joined
Compound
What symbol does the element Potassium have?
K
The state of matter (ice melting into water) is what kind of property?
Physical property
Burning paper is an example of what kind of change?
Chemical change
Is this equation balanced?
3 H2 + N2 -> 2 NH3
Yes!
The mass per unit volume of a substance.
Density
What symbol does the element Silver have?
Ag
Which would be the best property to help determine an unknown substance? A. Density, B. Flammability, C. Oxidation
A. Density
Every substance has its own unique density.
When a substance undergoes a __________ ________, its identity doesn't change.
Physical change
Why do we have to balance chemical equations?
To show that the Law of Conservation of Mass is true. Matter is neither created or destroyed.
Chemical reactions that release energy to their surroundings
What symbol does the element Mercury have?
Hg
No matter the size of the sample, the ______________ will always be the same for the same substance.
Density
Scrambling an egg is an example of what kind of change?
Physical change
Is this equation balanced?
CH4 + O2 -> 2 H2O + CO2
No,
CH4 + 2 O2 -> 2 H2O + CO2
C-1 C-1
H-4 H-4
O-4 O-4
When atoms of one or more substances rearranges to form one or more new substances.
Chemical Reaction
What element has the symbol Mn?
Manganese
A student wants to test the flammability of ice. He takes an ice cube and tries to burn it with a lighter, but it just melts.
Which of the properties demonstrated was a physical property and which was a chemical property?
Melting is a physical property and Flammability is a chemical property
Name 3 ways you can know a chemical change has occurred.
1) Temperature change/light, 2) new substance forms, 3) bubbles/gas, 4) odor, 5) color change
Balance this equation:
NO2 + H2O -> HNO3 + NO
3 NO2 + H2O -> 2 HNO3 + NO
N-3 N-3
O-7 O-7
H-2 H-2