Chemical reactions Flashcards
List the experimental observations indicating that a chemical reaction has occurred
- Change in colour
- Temperature change indicating an energy change
- Bubbles appear
- A solid appears or disappears
- Odour is produced
- A flame or light produced
What are the reactants of a chemical reaction?
Reactants are the substances that you start with in a chemical reaction. They’re like the ingredients you use when cooking or baking
They’re the things that “react” or change during the reaction to form new substances, which are called products.
What are the products of a chemical reaction?
new substances formed as a result of a chemical reaction.
finished dish you get after cooking or baking. They’re what you end up with once the reactants have reacted and changed.
Describe the difference between a physical and a chemical change.
In a physical change, the substance’s appearance or form changes, but its chemical composition remains the same. It’s like cutting paper into smaller pieces; it’s still paper.
In a chemical change, new substances are formed with different chemical compositions. It’s like baking a cake; the ingredients change to create something new.
List experimental observations that indicate a chemical change
Write word equations
Chemical reactions can be described using:
Word equations
e.g. carbon + oxygen → carbon dioxide
Formula equations
e.g. C + 2O → CO2
Balance chemical equations
To balance the equation, use coefficients.
A coefficient is a number placed in front of a chemical formula in an equation.
- Write the equation.
- Count atoms on each side.
- Add coefficients to make atoms equal on both sides.
- Check and revise as needed.
- Reduce coefficients to smallest whole numbers.
Symbols Used in Equations
+ separates two or more formulas
———> reacts to form products
triangle – the reactants are heated
(s) solid
(L) liquad ( water only)
(aq) any other liquad substance ( aqueous
(G) gas
