Empirical & Molecular Formula of Compounds problems
Empirical Formula of Compounds example question
Cyclohexanol, used in the manufacture of plastics, has the composition 71.95% C, 12.08% H, and 15.97% O by mass. Determine its empirical formula.
Solution to this Empirical Formula of Compounds practice problem is given in the video below!
Molecular Formula of Compounds example problem
Ethylene (molecular mass 28.0 u), cyclohexane (84.0 u), and 1-pentene (70.0 u) all have the empirical formula CH2. Give the molecular formula of each compound.
Solution to this Molecular Formula of Compounds practice problem is given in the video below!
Mass Percent Composition from Chemical Formulas problems
Mass Percent of Elements example question
Calculate the mass percent of each element in ammonium sulfate.
Solution to this Mass Percent of Elements practice problem is given in the video below!
Molar Mass problems
Molar Mass example question
Determine
(a) the total number of Cl atoms in 125 mL of liquid CCl4 (d = 1.589 g/mL) and
(b) the number of grams of carbon in 215 g of sucrose, C12H22O11 .
Solution to this Molar Mass practice problem is given in the video below!
Mole & Avogadro’s Number problems
Mole & Avogadro’s Number example question
Calculate
a) the mass in mg of mol Ag and
b) the number of oxygen atoms in 20.5 mol O2
Solution to this Mole & Avogadro Number practice problem is given in the video below!
Molecular & Formula Mass problems
Molecular Mass example question
Calculate, to three significant figures, the molecular mass of the following compounds:
1) P4
2) N2O4
3) H2SO4
4) CH3CH2COOH
Solution to this Molecular Mass practice problem is given in the video below!
Ions & Ionic Compounds problems
Formulas For Binary Ionic Compounds example question
Give the formula for each of the following ionic compound:
1) potassium sulfide
2) lithium oxide
3) aluminum fluoride
4) chromium (III) oxide
5) iron (II) sulfide
6) lithium nitride
Solution to this Ions & Ionic Compounds practice problem is given in the video below!
Laws of Chemical Combination problems
The Law of Conservation of Mass example question
What mass of magnesium oxide is formed when 1.500 grams of oxygen combines with magnesium?
Solution to this Law of Conservation of Mass practice problem is given in the video below!
Unit Conversions problems
Unit Conversion example question
Perform the following unit conversions:
1. 0.566 km to ft
2. 3.50 gal to fl-oz
Solution to this Unit Conversion practice problem is given in the video below!
Unit Conversion example problem
The pressure exerted by the atmosphere is 14.70 pounds per square inch. What is this pressure, expressed in kilograms per square meter?
Solution to this Unit Conversion practice problem is given in the video below!
Unit Conversion example
What is the volume in gallons of 10.0 kilograms of methanol, given that the density of methanol is 0.791 grams per milliLiter?
Solution to this Unit Conversion practice problem is given in the video below!
Significant Figures problems
Significant Figures example question
Find the number of significant figures in the numbers provided below:
2010
52.001
52.0010
0.00173
0.4000
1000
Solution to this Significant Figures practice problem is given in the video below!
Significant Figures Addition & Subtraction example problem
Perform the following operations and express the final answer with correct number of significant figures.
Solution to this Significant Figures practice problem is given in the video below!
Significant Figures Multiplication & Division example
Perform the following operations and express the final answer with the correct number of significant figures.
6.023 • 4.02 =
Solution to this Significant Figures practice problem is given in the video below!
Truth Tables problems
Truth Tables Conjunction Disjunction Negation example question
Complete the missing information in the following truth tables:
Solution to this Truth Table practice problem is given in the video below!
HARD Truth Table Conjunction Disjunction example
Find truth values and fill out a complete Truth Table for the following statement:
(p ∧ q) ∨ r
Solution to this Truth Table practice problem is given in the video below!
Truth Tables Conditional Converse Inverse Contrapositive example word problem
Find the truth values for the Converse, Inverse and Contrapositive conditional statements.
Given conditional statement: “If you live in Dallas, then you live in Texas.“
Solution to this Truth Table practice problem is given in the video below!
Linear Measure & Line Segments problems
Linear Measure example question
In the following examples, find the length of 
and the stars.
Solution to this Linear Measure practice problem is given in the video below!
Line Segment Variable example problem
Find the value of x if K is between J and L.
1. 
2. 
Solution to this Line Segment practice problem is given in the video below!
Line Segment Midpoint Coordinates example
Use the given endpoints of a line segment to find the midpoint of the line segment.
1. 
2. 
Solution to this Line Segment Midpoint practice problem is given in the video below!
Line Segment Endpoint Coordinates example question
Find the coordinates of A if 
is the midpoint of 
and C has coordinates 
.
Solution to this Line Segment Endpoint practice problem is given in the video below!
Line Segment Length example problem
Find the length of a line segment whose endpoint coordinates are 
and 
.
Solution to this Line Segment Distance practice problem is given in the video below!
Line Segment Midpoint Formula PROOF example
Show that the coordinates of a midpoint of a line segment whose endpoints are 
and 
can be shown with expression
Solution to this Line Segment Midpoint Proof practice problem is given in the video below!
Division Tricks problems
Egyptian Sidelight Division Method example question
Find the following quotients by using the Sidelight Method:
384 ÷ 32 =
192 ÷ 16 =
336 ÷ 12 =
Solution to this Division Trick practice problem is given in the video below!
Division of Whole Decimal or Rational Numbers example problem
Divide the following Whole and Rational Numbers using several methods:
152 ÷ 2 =
275 ÷ 5 =
0.15 ÷ 0.03 =
4.5 ÷ 0.09 =
4.5 ÷ 9 =
Solution to this Division Trick practice problem is given in the video below!
Square Number Tricks problems
Square Number Formulas example question
Find the following value by using three well-known Square Number formulas:
62 =
Solution to this Square Number practice problem is given in the video below!
Square of a Number Ending With 1 example problem
Find the following values by using a shortcut:
512 =
1012 =
1,0212 =
Solution to this Square Number practice problem is given in the video below!
Square of a Number Ending With 5 example
Find the following values by using a shortcut formula:
152 =
952 =
10,0152 =
Solution to this Square Number practice problem is given in the video below!
Square Number using Adjacent Perfect Square example question
Find the following values by using the adjacent perfect square for each number:
52 =
1012 =
172 =
Solution to this Square Number practice problem is given in the video below!
Addition Tricks problems
Whole Number Addition Trick example question
Add the following by using a shortcut:
47 + 23 =
72 + 128 =
121 + 369 =
Solution to this Addition Tricks practice problem is given in the video below!
Multiplication Tricks problems
Russian Peasant Multiplication Method example question
Find the following products by using the Russian Peasant method:
41 • 22 =
59 • 13 =
Solution to this Multiplication Tricks practice problem is given in the video below!
Lattice Multiplication Method example problem
Find the following products by using the Lattice method:
28 • 464 =
384 • 261 =
Solution to this Multiplication Tricks practice problem is given in the video below!
Multiplication of a 2-Digit Number by 11 example
Find the following products by using a shortcut:
22 • 11 =
47 • 11 =
97 • 11 =
Solution to this Multiplication Tricks practice problem is given in the video below!
Multiplication Trick example question
Find the following products by using a shortcut method:
46 • 49 =
47 • 48 =
Solution to this Multiplication Tricks practice problem is given in the video below!
Shaded Area in Geometric Figure puzzles
Shaded Area in a Square puzzle example question
In a unit square ABCD, point A is joined to the midpoint of BC, point B is joined to the midpoint of CD, point C is joined to the midpoint of DA, and point D is joined to the midpoint of AB. Find the area of the shaded region.
Solution to this Puzzle practice problem is given in the video below!
Shaded Area in a Square puzzle example problem
In a unit square ABCD, M is a midpoint of AD, and AC is a diagonal. Find the area of the shaded regions.
Solution to this Puzzle practice problem is given in the video below!
Shaded Area in a Square puzzle example
In the unit square ABCD, M is the midpoint and AC and BD are diagonals. Find the area of the shaded region.
Solution to this Puzzle practice problem is given in the video below!
Shaded Area in a Square puzzle example question
In the following unit square ABCD, M is the midpoint and BD is a diagonal. Find the area of the shaded region.
Solution to this Puzzle practice problem is given in the video below!
Shaded Area in a Square puzzle TRIGONOMETRY example problem
A square with side 1 is rotated around one vertex by an angle 
, where
and
.
Find the area of the shaded region.
Solution to this Puzzle practice problem is given in the video below!
Shaded Area in a Rectangle puzzle example
In the following rectangle, an isosceles triangle is drawn. Find the area of the shaded region.
Solution to this Puzzle practice problem is given in the video below!
Shaded Area in a Rectangle puzzle example question
In the following rectangle below, find the area of the shaded region.
Solution to this Puzzle practice problem is given in the video below!
Liquid Jug puzzles
Water Jug puzzle question
You have 2 water jugs. One jug can be completely filled with 3 gallons of water, and the other jug can be completely filled with 5 gallons of water. You need 4 gallons of water. How would you proceed?
Solution to this Puzzle practice problem is given in the video below!
Weight Scale puzzles
Eight Balls Placed on a Balancing Weight Scale puzzle example question
You have 8 balls all of the same size. 7 of them weigh the same, and one of them weighs slightly more. How can you find the ball that is heavier by using a balance and only two weighings?
Solution to this Puzzle practice problem is given in the video below!
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