Joint Questions with Correct Answers

AP CHEM MIDTERM EXAM Questions with Correct Answers


Question 1:
matter
Answer:
anything that has mass or takes up space: pure substances or mixtures


Question 2:
pure substances
Answer:
substance that is made up off only one kind of particle and is the same throughout: elements or
compounds


Question 3:
element
Answer:
a pure substance made of only one kind of atom, atoms all have same # of protons


Question 4:
compound
Answer:
two or more elements chemically combined in a specific ratio


Question 5:
mixture
Answer:
two or more substances (pure or mixture) physically combined


Question 6:
homogeneous mixture
Answer:
a mixture in which the composition is uniform throughout (air, salt water)

,Question 7:
heterogeneous mixture
Answer:
a mixture in which the composition is not uniform throughout with distinguishable parts (salad)


Question 8:
T/F a compound is always the same no matter how you make it
Answer:
true


Question 9:
T/F a mixture is always the same no matter how you make it
Answer:
false


Question 10:
physical properties
Answer:
can be measured w/o changing the chemical composition of the substance (density, melting
point)


Question 11:
chemical properties
Answer:
can only be measured after a substance reacts with another substance and changes
composition (flammability)


Question 12:
intensive properties
Answer:
do not depend on the amount of substance in a sample (boiling point)


Question 13:
extensive properties
Answer:
depend on quantity of a sample (mass, volume)

,Question 14:
physical change
Answer:
changes appearance of a substance but not composition (changes of physical state)


Question 15:
chemical change
Answer:
transforms a substance into a different substance (burning gas)


Question 16:
filtration
Answer:
separates a solid from a liquid in a heterogeneous mixture


Question 17:
distillation
Answer:
separates substances in a homogeneous mixture based on differences in boiling points


Question 18:
chromatography
Answer:
separates substances in a homogeneous mixture based on differences in intermolecular forces
and their abilities to dissolve in various substances (separating colors in ink on paper when
dipped in water)


Question 19:
SI units
Answer:
Mass = kg Length = m Time = s Temperature = K
Amount of substance = mol Electric Current = A (ampere) Luminous Intensity = cd (candela)

, Question 20:
metric prefixes
Answer:
Giga (G)= 10^9 Mega (M) = 10^6 Kilo (k) = 10^3
Deci (d) = 10^-1 (1/10) Centi (c) = 10^-2 (1/100)
Milli (m) = 10^-3 (1 thousandth) Micro (μ) = 10^-6 (1 millionth) Nano (n) = 10^-9 (1 billionth)
Pico (p) = 10^-12
Femto (f) = 10^-15


Question 21:
derived units
Answer:
units derived from SI base units (meters/second)


Question 22:
volume
Answer:
space occupied by a substance (m³, or cm³ = L)


Question 23:
density
Answer:
mass per unit of volume


Question 24:
1. zeros between nonzero digits = significant zeros at the beginning of a number = not
Zeros at end of a number are significant only if the number has a decimal point
product has same # of sig figs as the factor with the least # of sig figs(same with division)
sum/difference has same # of decimal places as measurement with least # of decimal places
Answer:
significant figures rules


Question 25:
John Dalton
Answer:
Dalton's atomic Theory: matter is composed of tiny indivisible particles called atoms (wrong,
not divisible), all atoms of one element are the same but are different from atoms of another
element (wrong, isotopes of the same element), and atoms combine in simple whole # ratios to
form compounds.