Chemical Reactions and Equations

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Questions and Answers

What are the signs that indicate a chemical reaction has occurred during the activities?

The signs include change in state, change in color, evolution of a gas, and change in temperature.

In the chemical equation Mg + O₂ → MgO, identify the reactants and the product.

The reactants are magnesium (Mg) and oxygen (O₂), while the product is magnesium oxide (MgO).

What is meant by an 'unbalanced' chemical equation?

An unbalanced chemical equation is one where the number of atoms of each element is not the same on both sides of the arrow.

Describe the role of the arrow in a chemical equation.

The arrow in a chemical equation points from the reactants to the products, indicating the direction of the chemical change. Signup and view all the answers

What precautions should one take when conducting Activity 1.3 with dilute hydrochloric or sulfuric acid?

One should handle the acid with care to avoid spills and skin contact, as acids can be corrosive. Signup and view all the answers

What does a word equation represent in a chemical reaction?

A word equation represents the reactants, products, and the direction of the chemical change using words. Signup and view all the answers

Can you explain what a skeletal chemical equation is?

A skeletal chemical equation is an unbalanced equation that does not have the same number of atoms of each element on both sides. Signup and view all the answers

How do chemical formulae contribute to writing chemical equations?

Chemical formulae simplify the representation of substances in a reaction, allowing for concise and clear equations. Signup and view all the answers

How do you determine if a chemical equation is balanced?

By counting the number of atoms of each element on both the left-hand side (LHS) and the right-hand side (RHS) and ensuring they are equal. Signup and view all the answers

What is the significance of the law of conservation of mass in balancing chemical equations?

It states that mass cannot be created or destroyed, meaning the total mass of reactants must equal the total mass of products. Signup and view all the answers

In the example of balancing the equation Fe + H2O → Fe2O3 + H2, what can you infer about the number of iron atoms?

The equation indicates that two iron atoms are produced in the products side, requiring a coefficient of 2 in front of Fe for balancing. Signup and view all the answers

Why is it incorrect to change subscripts in chemical formulas when balancing equations?

Changing subscripts alters the identity of the substance, which can lead to incorrect representations of the chemical reaction. Signup and view all the answers

What role do chemical formulas play in simplifying chemical equations?

Chemical formulas provide a concise way to represent reactants and products, making it easier to visualize and balance equations. Signup and view all the answers

Study Notes

Chemical Reactions

Magnesium ribbon burns with a dazzling white flame and changes to a white powder (magnesium oxide) due to a reaction with oxygen in the air.
Chemical reactions can be represented in word equations or chemical equations.
Observing changes in state, colour, gas evolution, and temperature can indicate a chemical reaction has occurred.

Chemical Equations

A word equation shows reactants (substances undergoing change) changing to products (new substances formed). Reactants are written on the left-hand side (LHS), and products are written on the right-hand side (RHS) separated by an arrow.
Chemical formulas can be used instead of words to create a chemical equation, making it more concise. For example, magnesium plus oxygen create magnesium oxide: Mg + O₂ → MgO.
A chemical equation is considered balanced if the number of atoms of each element is the same on both sides. An unbalanced equation is a skeletal chemical equation.

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Description

Explore the fundamentals of chemical reactions and equations in this quiz. Learn about the transformation of reactants into products, the importance of balancing equations, and the observable changes that indicate a reaction has occurred. Test your knowledge on word equations and chemical formulas.