CHEM 101L Lab 2: Rounding Rules

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Questions and Answers

What are the rules of rounding off numbers?

If the first digit to be dropped is less than 5, it and all following digits are dropped. If it is 5 or greater, all the following digits are dropped and the last retained digit is increased by 1.

What is rounding with magnitude?

When you round a large number, the correct magnitude is retained by replacing the dropped digits with placeholder zeros.

What are significant figures for multiplication/division?

The final answer has the same number of significant figures as the measurement with the fewest significant figures.

What are significant figures for addition/subtraction?

The final answer has the same number of decimal places as the measurement having the fewest decimal places. Signup and view all the answers

What is an equality in metrics?

If a quantity is expressed in two different metric units, a metric equality can be stated. Signup and view all the answers

What is a conversion factor?

The ratio of two values with a numerator and a denominator. Signup and view all the answers

Area of a rectangle is calculated using the formula: Area = x

Length, Width Signup and view all the answers

Volume of a rectangular solid is calculated using the formula: V = x x __

Length, Width, Height Signup and view all the answers

Volume of a cube is calculated using the formula: V = ______^3

L Signup and view all the answers

Volume of a cylinder is calculated as V = ______D^2H/4

π Signup and view all the answers

1 L is how many mL?

1000 mL Signup and view all the answers

1 qt is how many mL?

946 mL Signup and view all the answers

1 qt is how many pt?

2 pt Signup and view all the answers

1 in is how many cm?

2.54 cm Signup and view all the answers

1 lb is how many grams?

454 grams Signup and view all the answers

1 kg is how many grams?

1000 grams Signup and view all the answers

1 m is how many cm?

100 cm Signup and view all the answers

1 lb is how many oz?

16 oz Signup and view all the answers

Study Notes

Rounding Rules

If the first digit to be dropped is less than 5, drop it and the following digits.
If the first digit to be dropped is 5 or greater, drop it and increase the last retained digit by 1.

Rounding with Magnitude

To maintain the correct magnitude when rounding large numbers, replace dropped digits with placeholder zeros.
Example: 3.8765 x 10^4 s rounded becomes 3.88 x 10^4 s.

Significant Figures: Multiplication/Division

The final answer must have the same number of significant figures as the measurement with the fewest significant figures.
Example: 0.024 x 4.620 / 3.44 = 0.033575581 rounds to 0.034.

Significant Figures: Addition/Subtraction

The final answer should have the same number of decimal places as the measurement with the fewest decimal places.
Example: 2.11 + 104.056 + 0.1205 = 106.2865 rounds to 106.29.

Equality

A metric equality expresses a quantity in two different metric units.
Example: 1 m = 1000 mm illustrates a conversion between meters and millimeters.

Conversion Factor

A conversion factor is the ratio of two equivalent values expressed in different units.
Example: 1 m = 1000 mm implies 1000 mm equals 1 m.

Area of Rectangle

Area is calculated by the formula: Area = Length x Width.

Volume of Rectangular Solid

Volume is computed using: V = Length x Width x Height.

Volume of Cube

Volume can be determined using: V = L^3, where L is the length of a side.

Volume of Cylinder

Volume of a cylinder is calculated with: V = πD²H/4 or approximately V = 3.14D²H/4.
D represents the diameter while H is the height.

Metric Conversions

1 L = 1000 mL
1 qt = 946 mL
1 qt = 2 pt
1 in = 2.54 cm
1 lb = 454 grams
1 kg = 1000 grams
1 m = 100 cm
1 lb = 16 oz

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Description

Test your knowledge on rounding rules and methods for converting measurements in chemistry. This quiz focuses on number rounding and its impact on scientific calculations. Perfect for students in CHEM 101L.