Classification of Matter - MCQ and Fill in the blank questions with answer

Fill in the blanks

1. A substance that is made up of only one type of atom is called a(n)_______________.
2. Two or more substances physically combined form a(n)______________.
3. Two or more substances chemically combined are called a(n)_______________.
4. Sand is a good example of a(n) ______________ mixture.
5. _______________ elements, such as oxygen (O2), are found in nature in their elemental form as two-atom molecules.

MCQ

6. Which of the following substances cannot be broken down by ordinary chemical reactions?
a) water c) carbon dioxide b) gold d) glucose

7. Which of the following substances does not possess uniform composition?
a) pure water b) salt water c) helium gas d) salad

8. Which of the following is made up of only one type of atom?
a) NO b) He c) CO d) MgS

9. Which of the following represents a mixture?
a) NaCl(s) b) NaCl(l) c) NaCl(g) d) NaCl(aq)

10. Which of the following shows a ternary compound?
a) CO b) NaCl c) NH3 d) NaNO2

Answer Key
The actual answers will be shown in brackets, followed by the explanation.


1. [element]

2. [mixture]—You might have said “solution, “homogeneous mixture,” or
“heterogeneous mixture,” which are also true answers. “Mixture” is the
most general of the possible correct answers.

3. [compound]—Remember: The key is that the elements in a compound are
chemically combined. If the question asked about things that are physically
combined, the answer would have been a “mixture.”

4. [heterogeneous]—Sand is composed of particles of different substances,
mixed together in a non-uniform distribution.

5. [diatomic]—“Diatomic” means “two-atom,” so think of O2 or H2 when you
see it.

6. [B. gold]—Gold is an element, and elements can’t be broken down into
simpler substances by ordinary chemical means.

7. [D. salad]—We toss a salad to try to make its composition more uniform,
but it never becomes truly uniform.

8. [B. He]—NO, CO, and MgS all represent compounds. We can tell because
they all contain more than one capital letter and, therefore, more than one
elemental symbol.

9. [D. NaCl(aq)]—The “(aq)” indicates that the salt has been dissolved in water,
making it a mixture of two or more substances physically combined.

10. [D. NaNO2]—A ternary compound contains three different elements.
Sodium nitrite (NaNO2) contains the elements sodium, nitrogen, and
oxygen, so it fits the definition.