pH
True or False: a pH of 4 is weaker than a pH of 3
TRUE. The closer you are to 7, the weaker it is.
Give an example of a qualitative observation
Anything without numbers! Qualitative observations are description using the 5 senses.
Is sublimation is physical (P) or chemical (C) change?
Physical! --> Phase Change, molecules stay the same
True or False: Air is a pure substance.
FALSE. Air is made up of multiple gases!
What is the formula used to calculate density of an object?
D = M / V
Density is mass divided by volume.
Acids and bases both react with metals and litmus paper
False! Only acids react with metals. Both react with litmus paper.
What state of matter moves in the direction of gravity or applied force?
Liquid! Weak links allow it to take the shape of the container or move in the direction of force. Solids and gases do NOT do this
True or False
A chemical change is usually reversible
FALSE! Most chemical changes create new substances that cannot be reversed!
Is the following substance an element, compound, molecule? Select ALL that apply!
O--C--O
Compound and Molecule!
Made of 2+ atoms and the atoms are different!
During the density lab, we used a dropper to precisely measure the volume of water, what is the proper name of that piece of equipment?
Pipette!
What pH would the following substance be?
It turns pH paper green
It turns red litmus paper red
It turns blue litmus paper blue
NEUTRAL!
Provide an example of a characteristic (C) property and a non-characteristic property (NC).
C --> belonging only to one substance
NC --> belonging to multiple substances
What indicator is NOT found in a chemical change?
A) A solid forms
B) A smell is created
C) Light is created
D) A color changes
B! A smell is not one of the 5 indicators of a physical change (though it should be!)
True or False
Colloids and suspensions are examples of heterogeneous mixtures
False! Colloids are homogeneous
During the density lab, I layered a bunch of different substances on top that did not mix together.
If I had a graduated cylinder with oil, salt water and said (in that order), how many phases do I see?
3! Salt and water dissolve into eachother so I would see 1) salt water, 2) oil 3) sand
True or False
To test lemon juice I could dip pH paper into the water and to test a banana I could put a drop of universal indicator onto the peeled banana.
False! To test a banana, I would need to crush it and mix it with water before testing it.
Which letter represents a chemical property?
A) Boiling point
B) Reaction with Acid
C) Density
D) Mass
B --> Reaction with Acid
Chemical Property = How it INTERACTS with other substances.
True or False
If I leave my eaten apple on my desk for long enough it gets a brown colour, which is a physical change because it is still an apple.
False! Color change is a chemical change indicator!
In a homogeneous mixture, you see one phase. How would you describe the distribution of the particles?
Evenly distributed
12! You look at the atomic #
The number above the element symbol, which represents the # of protons and electrons
What colour of pH would a strong acid, like Windex turn?
Purple or blue!
How many plateau's (flat parts) do I see on a phase change diagram?
2!
One for solid --> liquid change & one for liquid--> gas change
During the lab, what indicator of a chemical change occurred when I mixed liquid Pb(NO3)2 with liquid KI?
Formation of a precipitate! Yellow solid substance
What does it mean to be immiscible?
When two substances do NOT mix!
What is the mass of a solid cube if the volume is 10 cm3 and the density is 2 g/cm3?
20 g!
D = M/V so then M=D x V