Find the total area of the tiles in Eddie’s path. Give your answer in the form $a\times {10}^k$ where $1\le a<10$ and $k$ is an integer.

Write an expression for $C$ in terms of $pH$.

Calculate the pH of the coffee.

The actual volume of the asteroid is found to be $6.074\times {10}^6 {\text{km}}^3$.

Find the percentage error in James’s estimate of the volume.

Calculate James’s estimate of its volume, in ${\text{km}}^3$.

Write down the value of the iron in the form $a\times {10}^k$ where $1\le a<10 , k\in \mathrm{\mathbb{Z}}$.

Find the $pH$ value for a solution in which the hydrogen ion concentration is $5.2\times {10}^{-8}$.

Find the hydrogen ion concentration in a solution with $pH 4.2$. Give your answer in the form $a\times 10k$ where $1\le a<10$ and $k$ is an integer.

Write your answer to part (b)(ii) in the form $a\times {10}^k$, where .