6 In a chemical reaction, the mass \(m\) grams of a chemical after \(t\) minutes is modelled by the equation
$$m = 20 + 30 \mathrm { e } ^ { - 0.1 t }$$
- Find the initial mass of the chemical.
What is the mass of chemical in the long term?
- Find the time when the mass is 30 grams.
- Sketch the graph of \(m\) against \(t\).