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Chemistry

GCSE

25 cm^3 of a solution of known 0.2M HCl is neutralised by titration by 21.5cm^3 of NaOH solution. Calculate then concentration of the NaOH solution to 3dp.

Recall n = c *(v/1000) if the volume is in Cm³.

Now, n(HCl)= 0.2 x (25.0/1000)

n(HCl) = 5x10^-3

Since the relationship stoichiometrically is 1:1 (H

Answered by Will F. • Chemistry tutor

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What is crude oil and how does fractional distillation work?

Crude oil is formed from detritus (dead living matter) of animal, plants and microscopic organisms under intense pressure and temperature. It is trapped under impervious rocks which stop the liquid and ga...

Answered by Amelia H. • Chemistry tutor

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Butane (C4H10) is an alkane. Complete the displayed structure of butane.

H H H H

H - C - C - C - C - H

H H H H

Answered by Joseph M. • Chemistry tutor

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25.00cm3 of sodium hydroxide was pipetted into a conical flask. It was titrated against 0.10mol/dm3 hydrochloric acid. The mean volume of acid needed was 24.00cm3. Calculate the concentration of sodium hydroxide used in the titration.

First write out the chemical equation:

HCl + NaOH -> NaCl + H₂0

Next construct a table with the information we have and in wha...

Answered by Matthew B. • Chemistry tutor

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What is the difference between exothermic and endothermic reactions?

The first law of thermodynamics states that energy can neither be created nor destroyed. Energy has to be used when breaking bonds, yet is formed when making bonds. This means that there will be an overal...

Answered by Alec M. • Chemistry tutor

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