Intro to Chem - Chem A

What is the first step in dimensional analysis?

• Calculate the conversion factor based on the given units.

• Determine the desired quantity and its units.

• Identify the given quantity and its units.

• Convert the units to a common system.

Answer explanation

The first step in dimensional analysis is to identify the given quantity and its units. This establishes the starting point for any conversions or calculations needed to analyze the dimensions involved.

Convert 2.5 liters to milliliters.

• 25000

• 250

• 25

• 2500

Answer explanation

To convert liters to milliliters, multiply by 1000. Thus, 2.5 liters x 1000 = 2500 milliliters. Therefore, the correct answer is 2500.

What are the SI units for length, mass, and time?

• inch, pound, hour

• centimeter, gram, minute

• mile, ton, day

• meter, kilogram, second

Answer explanation

The SI units for length, mass, and time are meter, kilogram, and second, respectively. These units are the standard measurements used in the International System of Units, making this the correct choice.

How many milliliters are in 1 liter?

• 10

• 500

• 100

• 1000

Answer explanation

There are 1000 milliliters in 1 liter, as 1 liter is defined as 1000 milliliters. Therefore, the correct answer is 1000.

The human esophagus us about 250 mm log. How long is that in inches? 1 in = 2.54 cm

• 10.64 in

• 9.84 in

• 11.35 in

• 8.84 in

Answer explanation

To convert 250 mm to inches, first convert mm to cm (250 mm = 25 cm). Then, use the conversion factor (1 in = 2.54 cm). So, 25 cm ÷ 2.54 cm/in = 9.84 in. Thus, the correct answer is 9.84 in.

What is the difference between accuracy and precision in dimensional analysis?

• Accuracy is the closeness of a measured value to the true value, while precision is the closeness of measured values to each other.

• Accuracy is the closeness of a measured value to the average value, while precision is the closeness of measured values to each other.

• Accuracy is the closeness of a measured value to the median value, while precision is the closeness of measured values to the mode value.

• Accuracy is the closeness of a measured value to the maximum value, while precision is the closeness of measured values to the minimum value.

Answer explanation

The correct choice defines accuracy as how close a measured value is to the true value, while precision refers to how close multiple measured values are to each other. This distinction is crucial in dimensional analysis.

The Olympic record for the high jump is just over 2.6 yards. What is that distance in feet?  (3 ft=1 yd)

• 0.867 ft

• 7.8 ft

• 8.07 ft

• 8.27 ft

Answer explanation

To convert yards to feet, multiply by 3. The Olympic record is just over 2.6 yards, so 2.6 x 3 = 7.8 feet. Therefore, the correct answer is 7.8 ft.

Which conversion factor would be needed?

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Which conversion factor would be needed?

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Which conversion factor would be needed?

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