Mass in Reactions
What happens to the mass of the reactants and products in a closed chemical reaction?
The mass of the reactants equals the mass of the products.
What is the word equation for hydrogen reacting with oxygen to make water?
Hydrogen + Oxygen → Water
What type of reaction gives off heat?
Exothermic
Name one piece of equipment used to measure temperature.
Thermometer
What does a Scoville unit measure?
Spice level
How can you measure the mass of a product in a chemical reaction?
By using a balance before and after the reaction to find the difference.
What symbol is used to show a chemical reaction has occurred?
→
Which type of reaction takes in heat?
Endothermic
What month of the year has 28 days?
All of them!
What happens to the rate of reaction when temperature increases?
It increases
What conclusion can you make if the mass of reactants and products are the same?
No mass was lost or gained; the reaction followed the law of conservation of mass.
Balance the following: H₂ + O₂ → H₂O
2H₂ + O₂ → 2H₂O
Which country invented ice cream
China
What is one risk when using hydrochloric acid, and how can it be reduced?
Risk of skin/eye irritation; reduced by wearing goggles and gloves.
Why does increasing temperature increase the rate of reaction?
Particles move faster and collide more frequently with more energy.
In a reaction, 10g of A reacts with 15g of B. What is the mass of the product C?
25g.
Write a word equation for the reaction: magnesium reacts with hydrochloric acid to form magnesium chloride and hydrogen.
Magnesium + Hydrochloric acid → Magnesium chloride + Hydrogen
Describe how energy profile diagrams differ for exothermic and endothermic reactions.
Exothermic diagrams show a drop in energy; endothermic show an increase.
What does DNA stand for?
Deoxyribonucleic acid
Why is it important to repeat experiments when investigating the rate of a reaction?
To ensure the results are reliable and to identify any anomalies.
Why might mass appear to change in a reaction involving gas?
Gas may escape into the air, making it seem like mass was lost.
Balance this symbol equation: Fe + O₂ → Fe₂O₃
4Fe + 3O₂ → 2Fe₂O₃
If the temperature of a reaction mixture increases, what kind of reaction is it likely to be?
Exothermic
If measuring temperature every 30 seconds, what should you do between readings?
Record the temperature
A student records the change in mass every 15 seconds. What graph should they plot?
Mass of reactant/product vs. time