Mathematical Methods · Unit 2 · Exponential functions · Indices and index laws
AI-marked practice questions tied to QCAA mark schemes for this exact LO. Free to start.
Start free practiceFull questions, answers and worked solutions unlock when you start a free practice session.
The mass of a single oxygen atom is $0.0000000000000000000000266$ kg. Express this mass in scientific notation. Hence, calculate the total mass of $2.5 \times 10^{23}$ oxygen atoms, giving your answer in scientific notation correct to 2 significant figures.
The mass of a water molecule is approximately $6.02 \times 10^{-26}$ kg. A typical raindrop contains approximately $1.4 \times 10^{21}$ water molecules. Which expression correctly represents the total mass of water molecules in one raindrop, in kilograms?
The mass of a hydrogen atom is \(1.674 \times 10^{-27}\) kg. The mass of a carbon-12 atom is \(1.993 \times 10^{-26}\) kg. (a) Determine how many times heavier a carbon-12 atom is compared to a hydrogen atom. Express your answer in scientific notation correct to three significant figures. [2 marks] (b) A sample contains \(3.5 \times 10^{23}\) hydrogen atoms. Calculate the total mass of hydrogen in the sample, in kilograms. Express your answer in scientific notation correct to two significant figures. [2 marks]