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3 years ago

Lastly, Snape thinks we should try one more calculation.

Chemistry

1 answer:

EleoNora [17]3 years ago

3 0

Answer:

E) 0.90

Explanation:

In TLC (Thin-Layer-Chromatography) retention factor RF is defined as the ratio between distance of the sample and the solvent front. RF is very important in chemistry to know the composition of any sample by comparison.

In the problem, as the sample has a distance of 0,20cm from the solvent front, the distance of the sample is:

2,0cm - 0,20 cm = 1,8 cm. Thus, RF is:

RF = 1,8cm / 2,0cm = 0,90

E) 0,90

I hope it helps!

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3 years ago

A volume of 25.36 ± 0.05 mL 25.36±0.05 mL of HNO 3 HNO3 solution was required for complete reaction with 0.8311 ± 0.0007 g 0.831

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Answer:

MOLARITY= 0.3092mol/l

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Explanation:

The equation of reaction is

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QUESTION1: CALCULATION FOR MOLARITY;

Molarity= gram mole of solute ÷ liters of solution

Where;

Mole of solute= mass ÷ molar mass

Therefore;

Mole of solute= 0.8311g ÷ 105.988g/mol= 0.0078515mol

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This is the Molarity of the solution

QUESTION2: CALCULATION FOR ABSOLUTE UNCERTAINTY;

Uncertainty (u) =√([0.05 ÷ 25.36]^2 + [0.001 ÷ 105.988]^2 + [0.0007 ÷ 0.8311]^2) × Molarity

Solving brackets gives

(0.00197161+0.00000943503+0.00084226) ×Molarity

Adding up gives

0.002823×Molarity

Therefore;

ABSOLUTE UNCERTAINTY= 0.002823×0.3092= 0.000873

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