CPC 2.3 Elements and Compound

Multiple Choice

What is an element?

• A mixture of different substances

• A pure substance that cannot be separated into simpler substances by physical or chemical means

• A compound that can be broken down into simpler substances

• A solution of various chemicals

Multiple Choice

How many elements occur naturally on Earth?

• around 50

• around 10

• around 100

• around 500

Multiple Choice

What does each element have that is unique?

• A unique charge

• A unique symbol

• A unique physical state

• A unique color

Multiple Choice

Why is the table called periodic?

• Because it organizes elements by their atomic number

• Because it arranges elements in alphabetical order

• Because the pattern of similar properties repeats from period to period

• Because it groups elements by their color

Multiple Choice

What do elements in the same group have in common?

• They have the same atomic number

• They have similar chemical and physical properties

• They have the same number of protons

• They have the same color

Multiple Select

What are the vertical columns in the periodic table called?

• Periods

• Rows

• Groups

• Sections

• Families

Multiple Choice

What are the horizontal rows in the periodic table called?

• Groups

• Families

• Periods

• Sections

Multiple Choice

What is a compound made up of?

• One element

• Two or more different elements

• Three or more identical elements

• Two or more different molecules

Multiple Choice

How are the elements in a compound combined?

• Randomly

• In a fixed ratio

• In a variable ratio

• By physical means

Multiple Choice

Most matter in the universe exists as what?

• Elements

• Atoms

• Compounds

• Mixtures

Multiple Choice

Which of the following is an example of a compound?

• Oxygen (O₂)

• Hydrogen (H₂)

• Table salt (NaCl)

• Helium (He)

Multiple Choice

Which of the following is NOT a compound?

• Water (H₂O)

• Carbon dioxide (CO₂)

• Sodium (Na)

• Table salt (NaCl)

Multiple Choice

What is often required to separate a compound into its elements?

• External energy, such as heat or electricity

• Internal energy, such as friction

• Tools, such as a graduated cylinder or filter

• a magnet

Multiple Choice

Which process is used to break down compounds into simpler substances?

• Physical means

• Chemical means

• Mechanical means

• Biological means

Multiple Choice

What process is used to chemically change water into its component elements?

• Combustion

• Electrolysis

• Filtration

• Distillation

Multiple Choice

What are the component elements obtained from the electrolysis of water?

• Hydrogen and Carbon

• Oxygen and Nitrogen

• Hydrogen and Oxygen

• Carbon and Oxygen

Multiple Choice

Does the law of definite proportions apply to samples of different sizes?

• Yes, it applies regardless of the sample size.

• No, it only applies to large samples.

• No, it only applies to small samples.

• Yes, but only if the samples are of the same size.

Multiple Choice

Which of the following statements is true according to the law of definite proportions?

• The elements in a compound can vary in proportion by mass.

• The elements in a compound are always in the same proportion by mass.

• The elements in a compound can vary in proportion by volume.

• The elements in a compound are always in the same proportion by volume.

Multiple Choice

How is percent by mass calculated?

• (mass of element / mass of compound) × 100

• (mass of compound / mass of element) × 100

• (mass of element + mass of compound) × 100

• (mass of element - mass of compound) × 100

Multiple Choice

What does the Law of Definite Proportions state about the percentages of elements in a compound?

• They vary depending on the sample amount.

• They remain the same despite differences in sample amount.

• They change with temperature.

• They depend on the method of extraction.

Multiple Choice

According to the table, what is the percent by mass of carbon in 20.00 g of granulated sugar?

• 6.50%

• 51.30%

• 42.20%

• 20.00%

Multiple Choice

According to the table, what is the percent by mass of carbon in 500.0 g of sugarcane?

• 42.20%

• 6.50%

• 51.30%

• 20.00%

Multiple Choice

What elements are present in both water (H₂O) and hydrogen peroxide (H₂O₂)?

• Hydrogen and Oxygen

• Hydrogen and Nitrogen

• Oxygen and Carbon

• Carbon and Hydrogen

Multiple Choice

In the compounds water (H₂O) and hydrogen peroxide (H₂O₂), what is the ratio of the mass of oxygen in hydrogen peroxide compared to water?

• 2:1

• 1:1

• 3:1

• 1:2

Multiple Choice

What is the same in both water (H₂O) and hydrogen peroxide (H₂O₂)?

• The mass of hydrogen

• The mass of oxygen

• The number of elements

• The chemical formula

Multiple Choice

Which of the following is true of elements?

• All elements are naturally existing.

• An element cannot be separated into simpler substances by physical or chemical means.

• Water is an element.

• Different sets of elements share similar physical properties, but they never share chemical properties.

Multiple Choice

How are elements in the periodic table organized?

• They are not organized in any particular pattern.

• They are organized alphabetically by their chemical symbols.

• They are organized into horizontal rows called periods and vertical columns called groups.

• They are organized into horizontal rows called groups and vertical columns called periods.

Multiple Choice

Which of the following is not a compound?

• water

• potassium iodide

• sodium chloride

• hydrogen

Multiple Choice

Which of the following is true of electrolysis?

• It separates water into one part hydrogen and one part oxygen.

• It causes the physical change of water into its component elements.

• It uses heat to break down a compound.

• It causes the chemical change of water into its component elements.

Multiple Choice

Copper(I) chloride and copper(II) chloride are both formed by the combination of copper and chlorine. The different masses of copper that combine with a fixed mass of chlorine in the two different compounds can be expressed as a small whole-number ratio. This ratio supports which law?

• the law of conservation of mass

• the periodic law

• the law of multiple proportions

• the law of definite proportions