Midterm Review

Select three important lab safety rules that should be followed when dealing with a spill.

• Smell the chemical carefully

• Wash your hands thoroughly

• Avoid touching or inhaling the powder

• Notify the teacher right away

• Wear gloves and goggles

Why is wearing gloves important after a spill?

• To protect your skin from possible harmful chemicals

• To keep your hands clean

• To make cleanup easier

• To identify the chemical by touch

Classify the spilled substance.

• An element

• A compound

• A suspension

What is the atomic number for sodium?

• 24.35

• 12.01

• 15.99

• 22.99

Which property best describes calcium (Ca) due to its position on the periodic table?

• It’s a noble gas and very unreactive

• It’s an alkaline earth metal and reacts with oxygen

• It’s a halogen and highly reactive

• It’s a transition metal and forms colored compounds

Elements in the same group of the periodic table have:

• A different number of outer electron shells

• Similar chemical properties

• The same atomic number

• Different numbers of valence electrons

Categorize the bond type of NaCl.

• Ionic

• Covalent

• Metallic

Bond type affects physical properties such as solubility and melting point.

• True

• False

Which statement about ionic bonds is true?

• They usually form between metals and nonmetals

• They involve sharing electrons equally

• They create substances with low melting points

• They result in gases at room temperature

You observe the spilled substance dissolves quickly when water is added, but you must wear gloves and goggles while cleaning it up. Based on the physical properties and safety information provided, which conclusion best explains the identity of the spilled substance?

• The substance is sodium chloride because it dissolves easily and is safe to handle without precautions.

• The substance is calcium carbonate because it does not dissolve well and is safe to handle.

• The substance is sodium hydroxide because it dissolves easily but requires safety precautions due to its harmful nature.

• The substance is calcium carbonate because it dissolves quickly and requires safety gear.