CHEMICAL VS. PHYSICAL CHANGES
A student measures 125g of ice in a closed beaker. An hour later, the ice melts into liquid water. State the type of change and the final mass.
Physical Change and 125g
In the chemical formula for Rust Fe2O3, state the exact count of each element.
What are 2 Iron (Fe) atoms and 3 Oxygen (O) atoms
In a solution of sugar water, identify the solute and the solvent.
Sugar (solute) and Water (solvent)
Bob and Jill mix lemonade powder into water until powder sits at the bottom and will no longer dissolve. State their solution's saturation state.
saturated
A small number written below and to the right of an element symbol that tells how many atoms of that specific element are in a formula.
subscript
Name the 7-word acronym (or memory phrase) used to remember the signs of a chemical change.
City Girls Like Their Cell Phones On (Color, Gas, Light, Temp, Creates new substance, Precipitate, Odor)
State the total number of Oxygen atoms present in ONE molecule of Glucose C6H12O6
6 Oxygen atoms
You have a solution of 12g of salt dissolved in 50mL of water. State the exact action needed to dilute this solution
adding more water (solvent)
Name the physical process of stirring or mixing a solution to increase particle movement and speed up dissolving.
agitation
A pure substance composed of two or more different elements chemically combined
compound
A candle wick burns, releasing heat, smoke, and light, while wax melts down the side. State which process is the chemical change.
burning the wick
True or False: There are 10 Oxygen atoms in the formula 5Na3CO2
True
Any solution where water is the liquid doing the dissolving is specifically classified as this
aqueous solution
Name the 3 standard physical methods used to increase the rate of dissolution of a solid solute.
Agitation (stirring), Increasing Temperature, and Increasing Surface Area (crushing)
The large number placed in front of a chemical formula that shows how many molecules or groups you have.
coefficient
A student mixes powder into a liquid and sees bubbles, a solid precipitate, a temperature increase, and powder dissolving. Name the ONE observation that is NOT evidence of a chemical change.
powder dissolving in the liquid
State the total number of atoms in ONE molecule of Calcium Nitrate, Ca(NO3)2
9 total atoms
Four beakers each contain 30mL of water and 15g of different solutes. After stirring, Substance D leaves 0g of solid remaining, while Substance A leaves 15g State which solution is most concentrated.
Substance D
True or False: A solution is saturated if you keep adding solute and it keeps dissolving without leaving any solid behind
False
The measurement of the amount of solute that is dissolved in a given quantity of solvent
concentration
An insoluble solid that forms and settles out of a liquid mixture during a chemical reaction is called this.
precipitate
Identify which of these formulas represents a compound containing exactly THREE different elements:
O3
NaHCO3
CaCO3
Fe2O3
CaCO3
Explain what happens to the overall concentration of a solution when you evaporate liquid solvent away.
concentration increases
Describe the visual evidence that proves a solution has transitioned from unsaturated to saturated.
undissolved solid solute sitting at the bottom of the container
The ability of a substance to dissolve in another substance.
solubility