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3 years ago

6

You pre-weigh a glass vial to hold your sample and find its mass to be 5.010 g. You add your sample to the vial and reweigh it o

n the same balance and find that the mass has increased to 6.130 g. What is the mass of the sample in grams

1 answer:

san4es73 [151]3 years ago

8 0

Answer : 1.12 grams

Yo find the mass of the sample, you take the increased mass and subtract the original mass.

6.130 - 5.010 = 1.12

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B. pH using activities = 2.46

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(ii) Calculate the ionic strength of the solution

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$I = \dfrac{1}{2} \sum_{i} {c_{i}z_{i}^{2}}\\\\I = \dfrac{1}{2}\left [0.04\times (+1)^{2} + 0.04\times(-1)^{2} + 0.00273\times(+1)^{2}\right]\\\\= \dfrac{1}{2} (0.04 + 0.04 + 0.00273) = \dfrac{1}{2} \times 0.08273 = 0.041$

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The HNO₃ will react with the NaOH to form 0.05 mol Na⁺ and 0.05 mol NO₃⁻.

The excess NaOH will react with 0.01 mol HA to form 0.01 mol Na⁺ and 0.01 mol A⁻.

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$\ln \gamma = -0.510z^{2}\sqrt{I} = -0.510(-1)^{2}\sqrt{0.10} = -0.510\times 0.32 = -0.16\\\gamma = 10^{-0.16} = 0.69$

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a = γc = 0.69 × 0.05= 0.034

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