Identify whether the statement is an observation, a law, or a theory.

a) An example of an inert or nonreactive gas is argon.

b) The arrangement of electrons in an element dictates its reactivity.

c) The chemical reactivity of elements follows a repeating pattern when they are listed in increasing atomic mass.

d) Fluorine is a highly reactive gas.

Classify each substance as a pure substance or a mixture. If it is a pure substance, classify it as an element or a compound. If it is a mixture, classify it as homogeneous or heterogeneous.

(i) carbon dioxide

(ii) white wine

(iii) copper

(iv) chicken stew

Different materials such as wood, vinyl, steel, and others were placed outdoors to determine the effect of acid rain on them. Their mass and appearance were recorded from time to time. Which of the following statements are true?

Classify the following as physical or chemical changes:

a. Water condenses on the surface of a cold glass.

b. Rust forms on the surface of an iron nail.

c. Black smoke rises when a candle is burned.

d. A drop of alcohol evaporates on a table.

An unknown element was observed to have the following properties:

1. It appears as a silvery liquid.
2. It has a density of 13.53 g/cm³ at room temperature.
3. It reacts with molecular iodine to produce a red solid.
4. It freezes at −38.83 °C and boils at 356.73 °C.
5. It forms a yellow solid when combined with dilute nitric acid.

Classify each property as physical or chemical.

Determine whether the following is intensive or extensive property:

a. refractive index

b. malleability

c. ductility

d. mass

e. melting point

Suppose you wanted to create your own temperature scale based on propyl alcohol (propanol) since you were unsatisfied with both the Celsius and Fahrenheit units. The melting point and boiling point of propanol on the Celsius scale are -126 °C and 97.2 °C, respectively. In the new scale, you define the melting point and boiling point of propanol at 0 °P and 150 °P, respectively. In terms of size, how does an propanol degree compare to a Fahrenheit degree?

Convert –62 °C to °F and K.

True or False: To express a number in a scientific notation, increasing the coefficient value means the exponent is negative while decreasing the coefficient value means the exponent is positive.

Convert the following number from scientific notation to regular form: 9.25×10^–3

Identify the property measured by each:

(a) 60 cm
(b)200 K
(c) 15 ms
(d) 250 g
(e) 5.4 kg/m³

Which of the following is not a SI base unit?