CH 1 - Chemistry Practice Problems: Properties, Changes, Mixtures, Scientific Notation, and Conversions

What color is elemental bromine?

Orange.

What happens to iron in the presence of air and water?

It turns to rust.

What can hydrogen do when ignited in air?

It can explode.

What is the density of titanium metal?

4.5 g/cm³.

What change occurs when bleach changes the color of a T-shirt from purple to pink?

Chemical change.

What occurs when water vapor condenses in the air on a cold day?

Physical change.

How do plants use carbon dioxide from the air?

To make sugar (chemical change).

What happens to butter when placed in the sun?

It melts (physical change).

Is water a mixture or a pure substance?

Pure substance (compound).

Is iron a mixture or a pure substance?

Pure substance (element).

Is blood a mixture or a pure substance?

Mixture.

Is brass a mixture or a pure substance?

Mixture.

Is the Pacific Ocean a mixture or a pure substance?

Mixture.

Is ammonia a mixture or a pure substance?

Pure substance (compound).

What is the scientific notation for 165.3?

1.653 x 10².

What is the scientific notation for 0.00047?

4.7 x 10⁻⁴.

What is 6.2 x 10¹¹ in standard notation?

620,000,000,000.

How many significant figures are in 0.0012 L?

Two significant figures.

How many significant figures are in 437,000 miles?

Three significant figures

How many significant figures are in 900.0 kg?

Four significant figures.

How many significant figures are in 106 J?

Three significant figures.

How many significant figures are in 320 seconds?

Two significant figures.

Convert 200,021 m to scientific notation with 2 significant figures.

2.0 x 10⁵ m.

Convert 555 miles to scientific notation with 2 significant figures.

5.6 x 10² miles.

Convert 0.000056723 g to scientific notation with 2 significant figures.

5.6 x 10⁻⁵ g.

Convert 4.37 dL to scientific notation with 2 significant figures.

4.4 x 10¹ dL.

What is the density of olive oil if 1 cup (237 mL) has a mass of 205 g?

Density = mass/volume = 205 g / 237 mL = 0.865 g/mL.

If the density of ethylene glycol is 1.11 g/cm³, what mass is required for 500 mL?

Mass = density x volume = 1.11 g/cm³ x 500 mL = 555 g.

What is the formula to convert Celsius to Kelvin?

K = °C + 273.15.

What is the formula to convert Fahrenheit to Celsius?

°C = (°F - 32) x 5/9.

What is the average melting point obtained from trials of 134, 136, 133, and 138°C?

Average = (134 + 136 + 133 + 138) / 4 = 135.25°C.

What is the percent error if the accepted value is 135°C and the average obtained is 135.25°C?

Percent error = |(135.25 - 135) / 135| x 100% = 0.19%.