Introductory Chemistry – Measurement & Calculation Essentials

A comprehensive set of Q&A flashcards covering scientific notation, metric prefixes, significant figures, accuracy and precision, unit conversions, density, and temperature scales from the provided Introductory Chemistry lecture notes.

What does scientific notation allow scientists to do?

Express very large or very small numbers as a product of a coefficient (between 1 and 10) and a power of ten.

In the number 2.14 × 10⁻³, what is the coefficient and what is the exponent?

Coefficient = 2.14, Exponent = –3.

Write 137,000,000,000 J in proper scientific notation.

1.37 × 10¹¹ J

Convert 0.000000142 g to scientific notation.

1.42 × 10⁻⁷ g

Convert 1.528 × 10⁵ kg to standard (decimal) form.

152,800 kg

What is the first step when multiplying numbers in scientific notation (e.g., (3.1 × 10⁴)(2.0 × 10²))?

Multiply the coefficients (3.1 × 2.0) and add the exponents (4 + 2).

How do you divide numbers written in scientific notation?

Divide the coefficients and subtract the exponent in the denominator from the exponent in the numerator.

Which calculator keys are commonly used to enter scientific notation?

EE, EXP, or ×10^.

Define a unit of measurement.

A quantity with an accepted value that allows results to be communicated between people.

Name the seven SI base units.

Kilogram (kg), meter (m), second (s), kelvin (K), candela (cd), ampere (A), mole (mol).

State the metric prefixes for 10³ and 10⁶.

kilo- (10³) and mega- (10⁶).

How many meters are in a kilometer?

1,000 m

How many milligrams are in a gram?

1,000 mg

How many amperes are in a megaampere (MA)?

1,000,000 A

Differentiate between accuracy and precision.

Accuracy refers to closeness to the true value; precision refers to how closely repeated measurements agree with each other.

State Rule 1 for identifying significant digits.

All non-zero digits and zeros between non-zeros are significant.

Are leading zeros (e.g., 0.0045) ever significant?

No; zeros to the left of the first non-zero digit are never significant.

When no decimal point is present, why are trailing zeros ambiguous?

Because it is unclear whether they indicate measured precision or are merely placeholders (e.g., 10,000).

What is an exact number?

A counted or defined value with no uncertainty (e.g., 1 kg = 1,000 g).

State the multiplication/division rule for significant digits.

The result has the same number of sig figs as the factor with the fewest sig figs.

State the addition/subtraction rule for significant digits.

Round the result to the least precise decimal place among the quantities.

What is dimensional analysis?

A method of converting units using conversion factors so that units cancel appropriately.

Give the conversion factor between meters and feet.

1 m = 3.280 ft

If 1 m = 10 dm, how many dm³ are in 1 m³?

1,000 dm³

How many cm³ are in 1 mL?

1 cm³

Define density.

Density (d) is mass divided by volume, d = m / V.

Explain how density predicts whether an object will float in water.

An object floats if its density is less than 1.00 g/cm³ (density of water at 25 °C).

A saltwater sample has m = 11.29 g and V = 10.4 mL. Calculate its density.

d = 1.09 g/mL (3 sig figs).

An antifreeze solution has d = 1.06 g/mL. What volume does 600.0 g occupy?

V = 566 mL (3 sig figs).

What is the mass of 1.32 L of aluminum (d = 2.70 g/cm³)?

3.56 × 10³ g (2 sig figs).

State the boiling and freezing points of water in °C.

Boiling: 100 °C; Freezing: 0 °C.

Provide the formula for converting °F to °C.

°C = (°F – 32) × 5⁄9

Provide the formula for converting °C to K.

K = °C + 273.15

What is absolute zero in Kelvin?

0 K

Convert 42 °F to Celsius.

≈ 5.6 °C

Convert 42 °F to Kelvin.

≈ 279 K

When should rounding to significant digits occur in a multi-step problem?

Only after the final calculation step.

Why is 1 L equal to 0.264 gal considered an exact conversion factor in chemistry problems?

Because it is a defined relationship used to relate metric and English volume units.

How is volume of a regular solid calculated before finding its density?

Multiply its length, width, and height (e.g., V = l × w × h for a rectangular solid).

What unit is commonly used for very small volumes in medicine?

The milliliter (mL, equivalent to 1 cm³).

If an IV flows at 95.0 cm³/h, how many liters are delivered in one day?

2.28 L (3 sig figs).

Why are zeros after a decimal point always significant (e.g., 1.100 mm)?

They indicate measured precision to that decimal place.

State the relationship between cm³, mL, and cc.

1 cm³ = 1 mL = 1 cc (cubic centimeter).

What power of ten corresponds to the prefix nano-?

10⁻⁹