Question 1

Which of the following best describes a compound?

Accepted Answer

A pure substance composed of two or more elements in a fixed proportion.

Question 2

Which of the following is an example of a homogeneous mixture?

Accepted Answer

Aire limpio

Question 3

Why is NaCl (table salt) considered a compound but not a molecule?

Accepted Answer

Because it forms a repeating ionic lattice, not discrete molecules.

Question 4

Which of the following statements about elements is correct?

Accepted Answer

Elements are substances made of only one type of atom.

Question 5

Which process would you use to separate a mixture but not a compound?

Accepted Answer

Filtration

Question 6

A sample of oro 16 k (16 karat gold) is best classified as:

Accepted Answer

A homogeneous mixture (alloy)

Question 7

Which of the following best explains why water (H$$_2O) is $$always considered a compound?

Accepted Answer

Because it contains hydrogen and oxygen in a fixed 2:1 ratio.

Question 8

Which of the following is NOT a characteristic of a substance classified as a mixture?

Accepted Answer

It has a fixed, definite composition.

Question 9

Which of the following substances is both a molecule and an element?

Accepted Answer

O$$_2$$

Question 10

A student is given a sample that appears uniform throughout and cannot be separated by filtration. However, it can be decomposed into simpler substances by a chemical reaction. How should this sample be classified?

Accepted Answer

Compound

Question 11

Which of the following best describes the difference between a molecule and a compound?

Accepted Answer

A molecule is any group of atoms bonded together; a compound is a molecule with different elements.

Question 12

Which of the following is a heterogeneous mixture?

Accepted Answer

Granito

Question 13

Which of the following best explains why air is not a pure substance?

Accepted Answer

Because it is a mixture of gases with variable composition.

Question 14

Which of the following is the smallest unit that retains the chemical properties of an element?

Accepted Answer

Atom

Question 15

A scientist analyzes a sample and finds it contains iron, chromium, and nickel, all distributed uniformly. How should this sample be classified?

Accepted Answer

Homogeneous mixture (alloy)

Question 16

Which of the following is true about a heterogeneous mixture?

Accepted Answer

Its different phases can be distinguished visually.

Question 17

Which of the following best describes why O$$_2 is $$not a compound?

Accepted Answer

Because it contains only one type of atom.

Question 18

Which of the following is a correct classification for 'refresco con burbujas'?

Accepted Answer

Mezcla heterogénea

Question 19

Which of the following best explains why gold 24 k is classified as a pure element?

Accepted Answer

Because it is made of only gold atoms.

Question 20

A sample of water from the ocean is analyzed. Which of the following best describes its classification?

Accepted Answer

Mezcla homogénea

Fundamentos de Química: Materia, Átomos, Elementos, Moléculas y Compuestos

Study Guide - Practice Questions

Study Guide - Flashcards