Equations and amounts · Grade 10
The limiting reactant
ChemAI · Worksheet
NameClassDate
Aim
The same piece of magnesium in a little and a lot of acid.
Before you start: what do you predict will happen? Why?
What you do
| Step | What I observed | |
|---|---|---|
| 1 | Add one piece of magnesium to each tube. | |
| 2 | Tube 1: the fizzing stops but magnesium is left. Which reactant ran out? (5 mL × 0.5 M = 0.0025 mol H⁺ < 2 × 0.002 mol) | |
| 3 | Tube 2: the magnesium disappears completely. Here the acid is in excess. Compare the hydrogen volumes: 30 mL and 48 mL. | |
| 4 | How many moles of hydrogen formed in tube 1 (mol)? |
Calculation
How many moles of hydrogen formed in tube 1 (mol)?
Questions
- Write a word or symbol equation for one reaction you observed.
- Explain your most important observation using particles, ions or energy.
- Was your prediction right? What would you change to get a more reliable result?