Q: The Law of Conservation of Mass can be mathematically expressed as:

$$\sum \text{mass}_{\text{reactants}} = \sum \text{mass}_{\text{products}}$$

Q: A graph shows atmospheric carbon dioxide concentration rising from 325 ppm in 1970 to 415 ppm in 2020. What is the increase in concentration over this period?

$$415\ \text{ppm} - 325\ \text{ppm} = 90\ \text{ppm}$$

Question 1

Which of the following best describes the science of chemistry?

Accepted Answer

The science that seeks to understand how matter behaves by studying what atoms and molecules do.

Question 2

Which statement about atoms is correct?

Accepted Answer

Atoms are the tiny particles that compose all common matter.

Question 3

Why is water a liquid at room temperature, according to its molecular structure?

Accepted Answer

Because water molecules are bent, which affects their interactions.

Question 4

Which of the following is an example of a chemical, as defined in chemistry?

Accepted Answer

All of the above

Question 5

Which step in the scientific method involves a tentative explanation that can be tested?

Accepted Answer

Hypothesis

Question 6

A scientist measures the mass of a container before and after burning a metal inside it and finds no change in mass. According to the scientific method, this is an example of:

Accepted Answer

An observation

Question 7

Which of the following best describes a scientific law?

Accepted Answer

A summary of the results of a large number of observations that predicts future ones.

Question 8

Antoine Lavoisier’s experiments with combustion led to which important scientific law?

Accepted Answer

The Law of Conservation of Mass

Question 9

The Law of Conservation of Mass can be mathematically expressed as:

Accepted Answer

$$\sum 	ext{mass}_{	ext{reactants}} = \sum 	ext{mass}_{	ext{products}}$$

Question 10

Which of the following is a theory, not a law or observation?

Accepted Answer

Matter is made of atoms.

Question 11

A student mixes 17.8 g of oxygen and 2.2 g of hydrogen to form water. What is the total mass of water formed, and which law does this demonstrate?

Accepted Answer

20.0 g; Law of Conservation of Mass

Question 12

Which of the following best describes the difference between a scientific law and a scientific theory?

Accepted Answer

A law summarizes observations and predicts future ones, while a theory provides a deeper explanation for those observations.

Question 13

Which of the following is NOT a step in the scientific method?

Accepted Answer

Ignoring experimental results

Question 14

A graph shows atmospheric carbon dioxide concentration rising from 325 ppm in 1970 to 415 ppm in 2020. What is the increase in concentration over this period?

Accepted Answer

$$415\ 	ext{ppm} - 325\ 	ext{ppm} = 90\ 	ext{ppm}$$

Question 15

Which of the following is an example of quantification in chemistry?

Accepted Answer

Measuring the temperature of a liquid as $$40^\circ$$ Celsius

Question 16

Why must hypotheses be falsifiable in the scientific method?

Accepted Answer

So further testing has the potential to prove them wrong.

Question 17

Which of the following best illustrates the application of the Law of Conservation of Mass in a real-world scenario?

Accepted Answer

A chef weighs ingredients before and after cooking and finds the total mass unchanged in a closed system.

Question 18

Which of the following statements is an observation, not a law or theory?

Accepted Answer

When a metal is burned in a closed container, the mass does not change.

Question 19

Which of the following is a key skill for success in chemistry, according to the study materials?

Accepted Answer

Curiosity and imagination to understand the 'why' of things.

Chapter 1: The Chemical World – Study Notes for Introductory Chemistry

Guida di studio - Domande di pratica

Study guide - Flashcard