Chemical Reactions
Grade 7 · Science · Chemistry of Life · Saskatchewan, Canada
Lesson Summary
Learn what happens when substances combine or break apart to form new substances.
Explanation
A chemical reaction occurs when the bonds between atoms break and new bonds form, creating new substances. The starting materials are called reactants and the new substances are called products. Signs that a chemical reaction has occurred include color change, gas production, temperature change, or formation of a precipitate. In every reaction, matter is conserved—the total mass of the reactants equals the total mass of the products.
Practice Questions
Q1: What is the difference between reactants and products?
Answer: Reactants are the substances you start with before the reaction, and products are the new substances formed after the reaction.
Q2: Name two signs that a chemical reaction has occurred.
Answer: A color change and the production of gas (bubbles) are two common signs. Others include temperature change and formation of a solid (precipitate).
Q3: If you start a reaction with 10 grams of reactants, how many grams of products will you get?
Answer: 10 grams. The law of conservation of mass states that matter is neither created nor destroyed in a chemical reaction, so the mass stays the same.
People Also Ask
What is Chemical Reactions in Grade 7 Science?+
Chemical Reactions is a lesson in the Chemistry of Life chapter of Grade 7 Science. It is part of the Saskatchewan, Canada school curriculum and covers key concepts that students need to understand at this level.
What grade level covers Chemical Reactions?+
Chemical Reactions is taught in Grade 7 as part of the Science curriculum in Saskatchewan, Canada.
How can I help my child with Chemistry of Life in Science?+
Start with the lesson summary and explanation on this page. Practice the questions provided, then use TutorTom for personalized, step-by-step help with Chemistry of Life topics.