Science-Chemistry

SEASHELLS AND OCEAN ACIDIFICATION – STUDY NOTES 1. What are seashells? Seashells are hard outer coverings made by some marine animals. They protect the animal from predators, injury and environmental conditions. Examples of animals with shells: * Oysters * Mussels * Clams * Snails 2. What are seashells made of? Most seashells are made of calcium carbonate (CaCO₃). Calcium carbonate is a compound made from: * Calcium (Ca) * Carbon (C) * Oxygen (O) 3. How do marine animals form shells? Marine animals take calcium and carbonate from seawater and combine them to make calcium carbonate. They then add this material to their shell as they grow. 4. What is ocean acidification? Ocean acidification is the process where the ocean becomes more acidic because it absorbs carbon dioxide (CO₂) from the atmosphere. Process: 1. Carbon dioxide enters the ocean. 2. It reacts with water. 3. The pH decreases. 4. The ocean becomes more acidic. 5. How does ocean acidification affect shell formation? Because shells are made of calcium carbonate, acidic water can damage them. Effects: * Shells become weaker. * Shell growth slows down. * Shells can dissolve over time. * Organisms use more energy to build shells. 6. Which marine organisms are affected? Many shell-forming organisms are affected, including: * Oysters * Mussels * Clams * Snails * Corals * Some plankton Effects on organisms: * Slower growth * Weaker shells * Lower survival rates * Disruption to food chains 7. Hydrochloric Acid and Calcium Carbonate Experiment Aim: To investigate how the concentration of hydrochloric acid affects the rate of reaction with calcium carbonate. Independent Variable: The concentration of hydrochloric acid. Dependent Variable: The reaction rate. Controlled Variables: * Mass of calcium carbonate * Volume of acid * Temperature * Size of calcium carbonate pieces Results: As hydrochloric acid concentration increased, the reaction rate increased. Conclusion: Higher acid concentrations cause calcium carbonate to react faster. 8. How does the experiment relate to ocean acidification? The experiment showed that acids react with calcium carbonate. Since seashells are made of calcium carbonate, increasing ocean acidity can damage shells and make it harder for marine organisms to build and maintain them. 9. Atoms Matter Revision Atom: The smallest particle of an element. Element: A pure substance made from one type of atom. Examples: * Oxygen * Carbon * Calcium Compound: Two or more different elements chemically joined together. Examples: * Carbon dioxide (CO₂) * Calcium carbonate (CaCO₃) Mixture: Substances combined but not chemically joined. Example: * Seawater 10. Conclusions You Could Use in the Test "The results show that as acid concentration increased, the reaction rate increased." "Ocean acidification makes it harder for marine organisms to build and maintain calcium carbonate shells." "Calcium carbonate is a compound because it contains calcium, carbon and oxygen chemically bonded together." "Seawater is a mixture because it contains water and dissolved salts that are not chemically bonded."

What are seashells?

Seashells are hard outer coverings made by some marine animals, protecting them from predators, injury, and environmental conditions.

Examples of animals with shells?

Oysters, Mussels, Clams, Snails.

What are seashells made of?

Most seashells are made of calcium carbonate (CaCO₃).

What is calcium carbonate composed of?

Calcium carbonate is composed of Calcium (Ca), Carbon (C), and Oxygen (O).

How do marine animals form shells?

Marine animals take calcium and carbonate from seawater and combine them to make calcium carbonate, which they add to their shells as they grow.

What is ocean acidification?

Ocean acidification is the process where the ocean becomes more acidic due to the absorption of carbon dioxide (CO₂) from the atmosphere.

What happens during ocean acidification?

Carbon dioxide enters the ocean, reacts with water, decreases pH, making the ocean more acidic.

How does ocean acidification affect shell formation?

Acidic water can damage shells, making them weaker, slowing growth, and leading to potential dissolution over time.

Which marine organisms are affected by ocean acidification?

Oysters, Mussels, Clams, Snails, Corals, and some plankton.

Effects of ocean acidification on organisms?

Slower growth, weaker shells, lower survival rates, and disruption to food chains.

Aim of the hydrochloric acid and calcium carbonate experiment?

To investigate how the concentration of hydrochloric acid affects the rate of reaction with calcium carbonate.

What is the independent variable in the experiment?

The concentration of hydrochloric acid.

What is the dependent variable in the experiment?

The reaction rate.

What controlled variables were used in the experiment?

Mass of calcium carbonate, volume of acid, temperature, size of calcium carbonate pieces.

What were the results of the experiment?

As hydrochloric acid concentration increased, the reaction rate increased.

Conclusion of the experiment?

Higher acid concentrations cause calcium carbonate to react faster.

How does the experiment relate to ocean acidification?

The experiment indicates that acids react with calcium carbonate; thus, increased ocean acidity can damage shells and hinder marine organisms' ability to build and maintain them.

Define an atom.

An atom is the smallest particle of an element.

Define an element.

An element is a pure substance made from one type of atom.

Examples of elements?

Oxygen, Carbon, Calcium.

Define a compound.

A compound is two or more different elements chemically joined together.

Examples of compounds?

Carbon dioxide (CO₂), Calcium carbonate (CaCO₃).

Define a mixture.

A mixture consists of substances combined but not chemically joined.

Example of a mixture?

Seawater.

Conclusions you could use in a test regarding acid concentration and reactions?

"The results show that as acid concentration increased, the reaction rate increased."

Conclusions regarding ocean acidification's impact?

"Ocean acidification makes it harder for marine organisms to build and maintain calcium carbonate shells."

Conclusion about calcium carbonate?

"Calcium carbonate is a compound because it contains calcium, carbon, and oxygen chemically bonded together."

Conclusion about seawater?

"Seawater is a mixture because it contains water and dissolved salts that are not chemically bonded."