2. Measurements in Chemistry

A liter is equivalent to 1 cm3 1 m3 1 mm3 1 dm3

1dm3

The speed of light is around 6.706×10^8 miles per hour. What is the speed of light in units of miles per minute?

1.117 x 10^7 miles per minute

What is the volume of a 5.30g piece of aluminum? The density for aluminum is 2.70gmL.

1.96 mL

A speed limit in a U.S. city is 65.0 miles per hour. Canadian cities express speed limits in kilometers per hour. Express the value in km/hr. (1.609 km=1 mile)

105 km/hr

Which of the following has 3 significant figures? Select all that apply. 123 12.3 123000. 1.23x10^4

123 12.3 1.23x10^4

In the process of vision, the light-sensitive pigment rhodopsin undergoes cis-trans isomerism in response to light in about 2×10^−10ms. How many seconds is this? Write the answer in scientific notation.

2 x 10^-13 s Note that the prefix m stands for "milli." A millisecond equals 1×10^−3 second. Use this to write 2×10^−10ms in seconds. 2×10^−10 ms×10^−3 sms=2×10^−13 s 2×10^−10ms equals 2×10^−13 seconds.

Complete the following operation to the correct number of significant figures: 85.2÷25.90348= 3.289 3.28 3.29 3.3

3.29

35 gigatons equals

3.5 x 10^10 tons The prefix "giga" means 109, so it can be written as the following: 35 gigaton = 35×10^9 tons To write the number in scientific notation, the decimal part must be between 1 and 10. Move the decimal point in 35 to the left one place, and, since this makes the number smaller by a power of 10, add 1 to the exponent on 10 to compensate 35 x 10^9 tons = 3.5 x 10^10 tons

Saltwater covers approximately 361,900,000 square kilometers of the earth's surface. Write the number of square kilometers of saltwater in scientific notation

3.619 x 10^8 square kilometers

If we wish to convert a value in years into days, a conversion factor we could use would be: 1 year/365 days 365 days/1 year 1 year/24 hours 24 hours/1 year

365 days/1year

Complete the following operation to the correct number of significant figures: 9.693+36.9=

46.6

The wavelength of yellow light is approximately 0.000000580m. Convert this quantity from meters to nanometers.

5.80 x 10^2 nm The prefix "nano" means 10^−9. To convert meters to nanometers, move the decimal point to the right 9 times, filling in zeros as needed, and then use a prefix symbol, n, to represent 10^−9. 0.000000580m=580×10^-9m=580nm Now, to write 580nm in scientific notation, move the decimal so that there is only one nonzero digit to the left of the decimal place. Therefore, the decimal should be moved two places to the left. The exponent on 10 will be equal to the number of places the decimal is moved. Therefore, the value written in scientific notation is as follows. 580nm=5.80×10^2nm Recall that if a trailing zero is on the right side of a decimal point, it is significant and should be included in the scientific notation.

Complete the following operation to the correct number of significant figures: 4.5×11.41=

51

You are guessing the age of a stranger whose actual age is 73. Which set of guesses represents low accuracy but high precision? 71, 73, 74 42, 89, 103 64, 63, 65 79, 71, 69

64, 63, 65

An object has a mass of 0.124kg and a volume of 1893mm^33. What is its density in grams per cubic centimeter?

65.5 gm/cm^3

If the accepted value for a measurement is 60.3 mL, which of the following sets of measurements is precise but not accurate? 56.7 mL, 87.3 mL, 28.9 mL 60.2 mL, 60.3 mL, 60.1 mL 76.5 mL, 76.4 mL, 76.3 mL all of the above

76.5 mL, 76.4 mL, 76.3 mL

Which of the following is true regarding significant figures? All zeros between significant digits are not significant. All zeros to the left of the decimal point are not significant. All nonzero digits are considered significant. All of the above.

All nonzero digits are considered significant.

Which of the following is not a rule regarding significant figures? All trailing zeros to the right of a decimal mark are significant. All nonzero digits are considered significant. All zeroes between significant digits are significant. All nonzero digits can be ignored.

All nonzero digits can be ignored.

Which of the following statements BEST describes the SI system of unit? An updated version of the English System of Measurement. An expansion of the metric system. Another version of the Imperial System of Measurement. The only system of measurement that is used throughout the world.

An expansion of the metric system.

The international metric system used in science, medicine, and industry is known as:

International System of Units

Which of the following must be true about a precise measurement? It typically contains many significant figures. It has very few significant figures. It is very close to the true value. It is far away from the true value.

It typically contains many significant figures.

What is the SI unit used to measure temperature? Joule Celcius farenheit Kelvin

Kelvin

What symbol would be used for a measurement in mega liters?

ML

A set of measurements that yield very similar results when repeated in the same manner are said to be: accurate precise both accurate and precise none of the above

Precise

Which of the following is a rule of significant figures in calculations? Round the result to the same number of digits as the number with the most number of significant figures. Round up if the digit to be dropped is less than 5. Round down if the digit to be dropped is less than 5. None of the above.

Round down if the digit to be dropped is less than 5

0.738×0.28 is 0.20664 but is rounded to 0.21. Which rule or rules are applied to this calculation? Select all that apply. Round the result to the same number of decimal places as the value with the least number of decimal places. Round the result to the same number of significant figures as the value with the least number of significant figures. Round down if the digit to be dropped is less than 5. Round up if the digit to be dropped is 5 or greater.

Round the result to the same number of significant figures as the value with the least number of significant figures. Round up if the digit to be dropped is 5 or greater.

Why is it important to use a standard system of measurement across all science disciplines? Science has unique measurements that need to be taken. Conversion factors are easily used between science disciplines. So that scientists around the world can easily compare experimental results. Science uses the oldest measurements to ensure accuracy.

So that scientists around the world can easily compare experimental results.

Explain when trailing zeros should be considered significant. When the number has no decimal point. When the number includes a decimal point. Trailing zeros are always significant. Trailing zeros are never significant.

When the number includes a decimal point.

In November 2018, the kilogram was redefined in terms of Planck's constant. Directly prior to this, the kilogram was based on: a cylinder of platinum-iridium alloy the mass of a liter of water the mass of a king's crown the mass of a gold bar

a cylinder of platinum-iridium alloy

Which is the longest distance? a meter a kilometer a megameter a terameter

a terameter A terameter is 10^12 meters, whereas a megameter is 10^6 meters and a kilometer is 10^3 meters.

A measurement is _____ if it yields results that are close to the accepted value. valid accurate precise none of the above

accurate

Non-zero digits are: never significant always significant significant if they are before a decimal significant if they are after a decimal

always significant

When determining significant figures within a number, non-zero digits are: never significant usually significant always significant only significant if they are before a decimal

always significant

What is the SI unit of "mole" used to measure? mass of a substance amount of a substance temperature of a substance time for substance to change phase

amount of a substance

What is the unit used for measuring current in the SI system? ampere candela meter gram

ampere

When adding numbers, the sum will have: as many decimal places as the number with fewest decimal places as many decimal places as the number with the most decimal places as many significant figures as the number with fewest significant figures as many significant figures as the number with the most significant figures

as many decimal places as the number with fewest decimal places

When dividing one number by another, the quotient will have: as many decimal places as the number with fewer decimal places as many decimal places as the number with more decimal places as many significant figures as the number with fewer significant figures as many significant figures as the number with more significant figures

as many significant figures as the number with fewer significant figures

Which of the following is NOT a unit used in the SI system? ampere atomic mass unit kilogram meter

atomic mass unit

Which prefix means one one-hundredth? centi deci milli kilo

centi

Which would NOT be an appropriate unit for density? g/mL kg/m3 g/s all of the above are acceptable

g/s

If object A and object B have the same density, but object A has greater mass, then object A must have:

greater volume

In some cases, volume can be found by cubing which of the following quantities? mass length time none of the above

length

What is the SI unit for measuring volume?

m^3

Which of the following is NOT a base unit used in the SI system of measurement? second milliliter mole meter

milliliter

Which of the following units is a derived SI unit (not one of the SI base units)? meter kilogram second newton

newton

Which is the shortest length of time? one microsecond one nanosecond one millisecond one decisecond

one nanosecond

Which of the following is NOT a SI base unit? m s oz cd

oz

The number of significant figures in a value is a display of the _________ of a measurement. precision accuracy both precision and accuracy none of the above

precision

In dimensional analysis, what is a conversion factor? accepted values for physical quantities theoretical quantities of matter experimental values for given quantities of matter ratios of physical quantities used to compare desired units

ratios of physical quantities used to compare desired units

The digits in a measurement, including the uncertain last digit, are known as: uncertainity digits precise measurements significant figures none of the above

significant figures

Today, the meter is based on: a meter stick the height of a king a fraction of the distance from the equator to the north pole the distance light travels in a particular fraction of a second

the distance light travels in a particular fraction of a second

Which zero in 0.10200 is not significant?

the first

What SI unit do we use when measuring distance?

the meter

Which of the following is NOT considered a SI unit of measurement? the pound the meter the kilogram the second

the pound

For a number written in scientific notation, 1.02×10−7, what does the exponent represent? the amount of zeros to add to the digit term how many times to multiply the digit term by itself the power of ten the digit term is multiplied by reliability of the digit term to the accepted value

the power of ten the digit term is multiplied by