Top answers

A sample of hydrochloric acid has a pH of 2.34. 
Write an expression for pH and calculate the concentration of this acid.

pH = -log([H+]) Therefore, 10^(-pH) = [H+] [H+] = 4.57x10^-3
CN
Answered by Charlie N. • Chemistry tutor
11937 Views

Explain the flow of ions during an action potential of a typical neurone

There are numerous ionic fluxes during an action potential, which involves depolarisation, repolarisation and hyperpolarsation. During depolarisation, voltage-gated sodium ion channels open. In turn, sodium ...
AS
Answered by Annie S. • Biology tutor
5521 Views

Question: What proportion of the clock is the area covered when the time is 12:10? (Here the question should indicate the time stated and shade in the proportion of the clock to be computed.)

The key to answering this question is for the student to realise that even though the area to be computed is a difficlut shape (an arc), the clock consists of 5 more arcs of the same shape. Once the student ...
AV
Answered by Annita V. • Maths tutor
3933 Views

Work out the value of 2a^2 + b^3 when a = 5 and b = –3

To work out the values you need to sub in a and b into the equation, giving you: 2(5) 2 + (-3) 3 From this we use the rules of BODMAS to first complete the orders and obtain: 2*25 + (-27). Again using BODMAS...
KM
Answered by Kyle M. • Maths tutor
5840 Views

Each day Chen buys pasta or a sandwich. Where Pasta costs £3.20 and Sandwich costs £2.75. For 45 days, the relative frequency of Chen buying a sandwich was one fifth. Altogether, how much did he pay?

Firstly work out how many days Chen bought a sandwich, which was one fifth of 45 days. So 45/5 = 9. We then multiply 9 by the cost of a sandwich, 9 2.75 = 24.75. The remaining days Chen must have bought Past...
KM
Answered by Kyle M. • Maths tutor
3862 Views