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2 years ago

how many grams of sodium hydroxide are required to dissolve in 232 g of water to make a 2.88 m solution

Chemistry

1 answer:

Gemiola [76]2 years ago

7 0

Grams of Sodium hydroxide : 26.72 g

<h3>Further explanation</h3>

Molality shows the number of moles dissolved in every 1000 grams of solvent.

m = n. (1000 / p)

m = Molality

n = Number of moles of solute

p = Solvent mass (gram)

Can be written :

$\tt m=\dfrac{mol~solute}{kg~solvent}$

mol solute(NaOH)

m=2.88

kg solvent(water)=232 g=0.232 kg

$\tt mol~solute=m\times kg~solvent\\\\mol~solute=2.88\times 0.232=0.668$

mass of NaOH

$\tt mass=mol\times MW\\\\mass=0.668\times 40~g/mol=26.72~g$

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AVprozaik [17]

Answer:

1.022ppm is the unknown concentration of the metal

Explanation:

Based on Lambert-Beer law, the increasing in signal of a detector is directly proportional to its concentration.

The unknown concentration (X) produces a signal of 0.255

99mL * X + 1mL * 100ppm / 100mL produces a signal of 0.502

0.99X + 1ppm produce 0.502, thus, X is:

0.255 * (0.99X + 1 / 0.502) =

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1.022ppm is the unknown concentration of the metal

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2 years ago

A 3.82 g piece of limestone contains 2.62 g of CaCO3

Kobotan [32]

Considering the definition of percentage by mass, the mass percentage of CaCO₃ is 68.59%.

<h3>What is mass percentage</h3>

The percentage by mass expresses the concentration and indicates the amount of mass of solute present in 100 grams of solution.

In other words, the percentage by mass of a component of the solution is defined as the ratio of the mass of the solute to the mass of the solution, expressed as a percentage.

The percentage by mass is calculated as the mass of the solute divided by the mass of the solution, the result of which is multiplied by 100 to give a percentage. This is:

$mass percentage=\frac{mass of solute}{mass of solution}x100$

<h3>Mass percentage of CaCO₃</h3>

In this case, you know:

mass of CaCO₃: 2.62 grams
mass of limestone: 3.82 grams

Replacing in the definition of mass percentage:

$mass percentage=\frac{2.62 grams}{3.82 grams}x100$

<u><em>mass percentage= 68.59 %</em></u>

Finally, the mass percentage of CaCO₃ is 68.59%.

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1 year ago

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3 years ago

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likoan [24]

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Part B Redox titrations are used to determine the amounts of oxidizing and reducing agents in solution. For example, a solution

MissTica

Answer:

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Explanation:

For the reaction:

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2 years ago