What is the formula for density?
mass/volume
Give an example of a substance
answers will vary: Water, Salt, Air, Gold, Diamonds, Copper
We can test __________________ to determine if two substances are the same or different.
properties
What are reactants?
The old stuff
Is melting an ice cube a chemical or physical change?
Physical Change
Which one of the following characteristics will not help you tell whether two solids are the same or different substances?
Color, hardness, shape, melting point
shape
Give an example of a mixture
answers will vary: Saltwater, Potting Soil, Rocks, Store Soap, Blood
What is the definition of a property?
Unique characteristic that helps identify substances.
What are products
The new stuff
Is burning Magnesium a chemical or physical change?
Chemical Change
In a bottle of layered liquids, where will the most dense liquid be?
the lowest level
Daily Double
How can soap be a mixture OR a substance?
List 4 different properties we have studied.
hardness
density
solubility
melting point
freezing point
evaporation point
What happens to atoms during a chemical reaction?
The atoms of the reactants are rearranged to form the products.
Double jeopardy
What is one ingredient that colonist use in the soap making process that was different than ours?
A scientist has two containers. Inside each container is a blue liquid. The liquids are substances. What are two ways the scientist can use to help find out whether these two liquids are both the same substance?
check:
density, color, freezing point, evaporation point
Soda contains a large amount of sugar. Why can't it be seen in the liquid?
The sugar dissolves in the soda.
Double jeopardy
What phenomenon did we recreate with the copper strips and vinegar?
Is this a chemical rxn, why or why not?
yes because the atoms are rearranged
Mr. Smith
You have a substance with a mass of 20g and a volume of 2cm3. What is the density?
10 g/cm3
Why is water a substance but Kool-Aid is not?
Water is the same all of the way through. When Kool-Aid is added, the amount of the Kool-Aid could be different in different sample areas, and the Kool-Aid can be separated and removed from the water.
Why is density a property but mass is not?
The mass of an object can change, but the density is a ratio of the volume and the mass.
Why does mass not change during a chemical reaction?
the product is only made out of atoms that were originally in the reactants.
What is the name of a solid formed during a chemical reaction?
A precipate