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What is the difference between a base unit and a derived unit?

Base units are defined units based on specific objects or events in the physical world. Derived units are defined by combining base units.

Chlorine boils at 239 K. What is the boiling point of chlorine expressed in degrees Celsius?

-34C

What is the temperature of absolute zero measured in C?

-273C

You live 6 kilometers from your school. How many meters do you live from school?

6 km x 1000 m/km = 6000 m

How many seconds are there in a millisecond?

1 sec/1000 milliseconds = 0.001 seconds

1 cubic centimeter is equivalent to

1 milliliter

Explain in terms of density why a grocery bag containing all canned goods is harder to lift than a grocery bag containing all paper goods

Canned goods are more dense than paper goods. They have more mass per unit volume. Thus, for the same volume, the canned goods have more mass than the paper goods. The greater mass is more difficult to lift.

The meter is defined as

100 cm.

If the temperature changes by 100 K, by how much does it change in C?

100C

How can you obtain an object's volume if you know its density and its mass?

Answers may vary. Students should note that density is defined as the mass of an object divided by its volume. Thus, algebraically, you can determine that an object's volume is equal to its mass divided by its density.

The liter is the base unit of density.

False

When measuring length, 20 decimeters is greater than 20 centimeters

True

How many centimeters are in a meter?

100 cm

All of the following are examples of units except

weight

The SI base unit for time is the

second

Which of the following volumes is the smallest?

one millimeter

What is the boiling point of water in kelvins?

373 K

16m × 2.82m × 0.05m

2 m3

How many significant digits are there in 6.023 x 1023 molecules?

There are four significant digits in 6.023 x 1023 molecules.

1.056 mL

4

(1.6 x 10 12) ÷ (8.01 x 10 23)

2.0 X 10 -12

12.90 s

4

You calculate that your semester average in history is 97.5. When you get your report card, your average is 96. What was the percent error of your calculation?

1.6%; Solution: percent error = error/accepted value x 100%, percent error = (97.5 - 96)/96 x 100% = 1.5625% = 1.6%

If two measurements are very close to each other, then they are ____.

precise

You calculate that 213,000 m/s is the answer to a problem. What can you conclude about your answer?

It has three significant figures.

Poor precision in scientific measurement may arise from

both human error and the limitations of the measuring instrument.

Three different people weigh a standard mass of 2.00 g on the same balance. Each person obtains a reading of 7.32 g for the mass of the standard. These results imply that the balance that was used is ____.

precise

Nancy is asked to use her calculator to find the volume of a cylindrical canister that has a radius of 10.55 cm and a height of 12.56 cm. Which answer is the most accurate? Volume of a cylinder can be calculated using the following equation: V=πr2h

4392 cm3

Which variable is plotted on the x-axis?

independent

The three most common data patterns seen are:

Proportionality, linearity and inverse proportionality

base unit

A defined unit in a system of measurement that is based on an object or event in the physical world and is independent of other units.

second

The SI base unit for time.

meter

The SI base unit for length.

kilogram

The SI unit for mass; about 2.2 pounds.

derived unit

A unit defined by a combination of base units.

liter

The metric unit for volume equal to one cubic decimeter.

density

The ratio of the mass of a substance to the volume of the substance.

kelvin

The SI base unit of temperature.

accuracy

Refers to how close a measured value is to an accepted value.

precision

Refers to how close a series of measurements are to one another; precise measurements show little variation over a series of trails, but may not be accurate.

percent error

The ratio of an error to an accepted value.

significant figure

The number of all known digits reported in measurements, plus one estimated digit.

graph

A visual representation of information, such as a circle graph, line graph, or bar graph, that can reveal patterns in data.