Chemistry Concepts for Grade 11

What is the atomic number of carbon?

• 7

• 6

• 12

• 5

Define the term 'mole' in chemistry.

• A mole is the volume of a gas at standard temperature and pressure.

• A mole is a unit of mass equivalent to one gram.

• A mole is the amount of substance containing 6.022 x 10^23 entities.

• A mole is a measure of temperature in chemical reactions.

What is the chemical formula for water?

• H2O

• H2O2

• HO2

• O2H

Explain the difference between ionic and covalent bonds.

• Ionic bonds are formed only in metals, while covalent bonds occur in non-metals only.

• Ionic bonds involve sharing electrons, while covalent bonds involve attraction between ions.

• Ionic bonds involve electron transfer and attraction between ions, while covalent bonds involve electron sharing between atoms.

• Covalent bonds are stronger than ionic bonds due to their electron transfer nature.

What is the pH scale and what does it measure?

• The pH scale indicates the color of a solution.

• The pH scale measures the density of a solution.

• The pH scale measures the temperature of a solution.

• The pH scale measures the concentration of hydrogen ions in a solution.

Describe the process of photosynthesis in terms of chemical reactions.

• 6CO2 + 6H2O + light energy -> C6H12O6 + 6O2

• 6O2 + light energy -> 6CO2 + C6H12O6

• C6H12O6 + 6O2 + light energy -> 6CO2 + 6H2O

• 6CO2 + 6H2O -> C6H12O6 + 6O2

What is the law of conservation of mass?

• Mass can be created in chemical reactions.

• Mass is conserved in chemical reactions.

• Mass is only conserved in physical reactions.

• Mass is lost during physical changes.

Identify the main components of an atom.

• Protons, neutrons, and electrons

• Neutrons, electrons, and photons

• Protons, positrons, and muons

• Protons, electrons, and quarks

What is the significance of the periodic table in chemistry?

• The periodic table is significant in chemistry as it provides a systematic arrangement of elements, facilitating the understanding of their properties and relationships.

• It lists elements in alphabetical order without any scientific basis.

• It is a historical document with no relevance to modern chemistry.

• It categorizes elements based on their atomic weights only.

Explain what a catalyst does in a chemical reaction.

• A catalyst is a substance that is consumed in a chemical reaction.

• A catalyst slows down a chemical reaction by increasing the activation energy.

• A catalyst speeds up a chemical reaction by lowering the activation energy.

• A catalyst changes the products of a chemical reaction to form new substances.