Question

1. for the following questions determine if the statement is true or false.

if the statement is false correct the statement below.

______ all matter is composed of tiny particles called atoms

______ you can determine the mass of an atom by adding the protons and electrons

______ when you change the number of neutrons in an atom you create an isotope

______ elements in the same group (column) have similar chemical properties

______ if hydrogen gas is produced in a reaction you can test it by hearing a popping sound with a burning splint

______ a solution is two atoms combined in fixed proportions

______ a neutron can be best described as having a relative mass of 0 and negative charge

______ the symbol for boron is be.

______ if oxygen gas is produced in a reaction you can test it by hearing a popping sound with a glowing splint

______ the compound \\(\text{al(oh)}_3\\) has 1 aluminum, 1 oxygen and 3 hydrogen atoms.

1. fill in the blanks below to make correct statements.

a) matter can be classified into two main categories:
______________________ and pure ______________________

b) name the two types of mixtures: ______________________ and ______________________

Explanation:

The questions test fundamental concepts in introductory chemistry.

• Matter is composed of atoms.
• Atomic mass is concentrated in the nucleus, which contains protons and neutrons; electrons have negligible mass.
• Isotopes are atoms of the same element with different numbers of neutrons.
• Elements in the same periodic group share chemical properties due to having the same number of valence electrons.
• Hydrogen gas burns with a characteristic "squeaky pop" sound when exposed to a flame.
• A solution is a homogeneous mixture, not a chemical compound with fixed atomic ratios.
• Neutrons have a relative mass of approximately 1 atomic mass unit and carry no electrical charge.
• The chemical symbol for Boron is B, while Be represents Beryllium.
• Oxygen gas supports combustion and is tested by its ability to relight a glowing splint.
• The subscript outside the parentheses in \(\text{Al(OH)}_3\) multiplies all atoms inside, yielding 3 oxygen and 3 hydrogen atoms.
• Matter is broadly classified into mixtures and pure substances, and mixtures are further categorized as homogeneous (uniform composition) or heterogeneous (non-uniform composition).

Answer:

1)

• True
• False. You can determine the mass of an atom by adding the protons and neutrons.
• True
• True
• True
• False. A compound is two or more different atoms chemically combined in fixed proportions. (Alternatively, a solution is a homogeneous mixture of two or more substances.)
• False. A neutron can be best described as having a relative mass of 1 and neutral (zero) charge.
• False. The symbol for Boron is B. (Be is the symbol for Beryllium.)
• False. If oxygen gas is produced in a reaction you can test it by seeing if it relights a glowing splint.
• False. The compound \(\text{Al(OH)}_3\) has 1 aluminum, 3 oxygen and 3 hydrogen atoms.

2)
a) mixtures and pure substances
b) homogeneous and heterogeneous