Chemistry Chapter 3

Round 0.000718 kilograms to two significant figures.

0.00072 kilograms

The accepted value of a length measurement is 200 cm, and the experimental value is 198 cm. What is the percent error?

1%

All metric units of length are based on multiples of

10

Round 100.1°C to 1 significant figure.

100°C

Round 155 cm to two significant figures.

160 cm

In the measurement 43.52 cm, which digit is the most uncertain?

2

The correct number of significant figures in the measurement 6.80 m.

3

503,000,000 written correctly in scientific notation

5.03 x 10^8

Round 65.145 meters to three significant figures.

65.1 meters

Round 65.145 meters to 4 significant figures.

65.15 meters

P or A A single measurement is within 1% of the correct value.

A

What is true about numbers expressed in scientific notation?

A number expressed in scientific notation is written as the product of a coefficient and a power of 10. The power of 10 is called the exponent. The coefficient is always a number greater than or equal to one and less than ten.

What is true about significant figures?

Every nonzero digit in a reported measurement is assumed to be significant. Leftmost zeros acting as placeholders in front of nonzero digits in numbers less than one are not significant. All rightmost zeros to the right of the decimal point are always significant. Zeros to the left of the decimal point that act as placeholders for the first nonzero digit to the left of the decimal point are not significant.

kelvin

K

For an experimental measurement, the experimental value minus the accepted value is the ______.

error

An answer is as precise as the most precise measurement from which it was calculated.

false

Is the following sentence true or false? The value of an error must be positive.

false

The International System of Units (SI) is a revised version of the

metric system

If a thermometer is calibrated to the nearest degree, to what part of a degree can you estimate the temperature it measures?

one tenth of a degree

Relative error is also called _______.

percent error

second

s

Why are numbers in chemistry expressed in scientific notation?

Numbers used in chemical calculations are often very large or very small. Writing out all the zeros in such numbers can be very cumbersome. Scientific notation makes it easier to work with these numbers.

P or A Eight measurements were spread over a wide range.

P

P or A Four of five repetitions of a measurement were numerically identical, and the fifth varied from the others in value by less than 1%.

P

What is the meaning of "accepted value" with respect to an experimental measurement?

The accepted value is the correct value based on reliable references.

To decide whether a measurement has good precision or poor precision, the measurement must be made more than once.

True

List two situations in which measurements have an unlimited number of significant figures.

When the measurement involves counting. When the measurement involves exactly defined quantities.