Mass stays the same in a reaction
Grade 8 Science Worksheet - Challenge Me
Circle the best answer, or write your answer on the line.
In a teacher's sealed flask, 84 g of baking soda reacts with 60 g of the acid in vinegar. Sodium acetate and water total 100 g. What mass of carbon dioxide formed, Ari?
A stove flame joins 16 g of methane with 64 g of oxygen. It makes 44 g of carbon dioxide and some water. What mass of water forms, Bo?
In Esme's cells, 180 g of glucose and 192 g of oxygen can release energy, making 264 g of carbon dioxide and some water. What mass of water?
Jun's mass graph is flat at 500 g, falls to 492 g, then levels off. Which story fits the graph?
- A tablet fizzed in an open flask until it stopped
- Mass was destroyed while the tablet fizzed
- Water was poured in at 2 min
- A sealed flask leaked air in
Kira's mass graph rises slowly from 200 g to 206 g over 6 days. Which story fits the graph?
- Steel wool rusted in a sealed jar
- Rust made new matter from nothing
- Water evaporated from the dish
- Steel wool rusted in an open dish
Luz's mass graph stays flat at 350 g while the liquid changes color. Which story fits the graph?
- A gas escaped from an open flask
- Mass was made and destroyed in equal amounts
- No reaction, since the mass stayed the same
- A reaction ran in a sealed flask
A teacher lights a candle under a sealed glass jar on a scale. Milo predicts the reading. What happens to it?
- It drops: the smoke weighs nothing
- It doubles
- It drops: burning destroys wax
- It stays the same
Steel wool sits in an open dish on a scale for a week and rusts. What does Pia predict for the reading?
- It stays the same: mass is conserved
- It drops: rusting wears away iron
- It drops to 0 g
- It rises as oxygen joins
Tala says a burned log proves that burning destroys mass. Agree or disagree?
- Disagree: ash is heavier than the log
- Disagree: the mass left as gases
- Agree: the ash is lighter, so mass was destroyed
- Agree: fire uses up matter
Zee says that since mass is conserved, an open cup's reading can't change while a tablet fizzes. Agree or disagree?
- Disagree: escaping gas lowers the reading
- Disagree: the reading rises
- Agree: conserved means the reading stays put
- Agree: no reaction changes a reading