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3 years ago

Calculate the pH of a solution in which [OH–] = 4.5 × 10–9M.

Chemistry

1 answer:

posledela3 years ago

7 0

Answer:

5.65 is the pH.

Explanation:

I am assuming that you are asking for confirmation on your answer. The answer is 5.65.

You would do:

[pOH] = -log[OH-]

= -log[4.5*10^-9]

equals about 8.3468

To find pH your would subtract the pOH from 14.

14-8.3468 = 5.65 << Rounded to match the answer choices.

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What is the main type of weathering in deserts? weathering by organic acids chemical weathering physical weathering

Solnce55 [7]

Answer:

chemical

Explanation:

Chemical weathering, which is the decomposition of a rock by the alteration of its chemical composition.

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3 years ago

A solution of potassium cyanide, KCN, is made by dissolving 3.2 g of KCN in water. When this solution reacts with excess hydroch

Rama09 [41]

Answer:

22.7%

Explanation:

We must first put down the equation of reaction to guide our work while solving the problem.

KCN(aq) + HCl (aq)--> KCl(aq) + HCN(aq)

The questions specifically state that HCl is in excess so KCN is the limiting reactant.

Number of moles of KCN reacted= mass of KCN reacted / molar mass of KCN

Mass of KCN reacted= 3.2 g

Molar mass of KCN= 65.12 g/mol

Number of moles of KCN= 3.2/65.12 g/mol= 0.049 moles

Theoretical yield of HCN is obtained thus;

From the reaction equation;

1 mol of KCN produced 1 mole of HCN thus 0.049 moles of KCN will produce 0.049 moles of HCN.

Mass of HCN = number of moles ×molar mass

Molar mass of HCN= 27.0253 g/mol

Hence mass of HCN produced= 0.049mol × 27.0253 g/mol= 1.32g of HCN

Actual yield of HCN= 0.30g

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% yield= 0.30/1.32 ×100

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3 0

4 years ago

Read 2 more answers

3) Calculate the percent by mass of 3.55 g NaCl dissolved in 88 g water.

kotykmax [81]

Answer:

The percent by mass of 3.55 g NaCl dissolved in 88 g water is 3.88%

Explanation:

When a solute dissolves in a solvent, the mass of the resulting solution is a sum of the mass of the solute and the solvent.

A percentage is a way of expressing a quantity as a fraction of 100. In this case, the percentage by mass of a solution is the number of grams of solute per 100 grams of solution and can be represented mathematically as:

$Percent by mass=\frac{mass of solute}{mass of solution} *100$

In this way it allows to precisely establish the concentration of solutions and express them in terms of percentages.

In this case:

mass of solute: 3.55 g
mass of solution: 3.55 g + 88 g= 91.55 g

Replacing:

$Percentbymass=\frac{3.55}{91.55}*100$

Percent by mass= 3.88%

<u><em>The percent by mass of 3.55 g NaCl dissolved in 88 g water is 3.88%</em></u>

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3 years ago

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Sholpan [36]

Answer:

Redox

Explanation:

Reduction is gain of electrons

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3 years ago

How does one recognize a redox reaction?

nika2105 [10]

Answer:

Explanation:

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3 years ago