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3 years ago

Help pls! Answer all of it. Idk if what I wrote is correct.

Chemistry

1 answer:

trasher [3.6K]3 years ago

8 0

The reaction is actually endothermic because delta H is positive, indicating that it absorbing heat.

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A 3.140 molal solution of NaCl is prepared. How many grams of NaCl are present in a sample containing 2.692 kg of water

S_A_V [24]

Answer:

494.49 g of NaCl.

Explanation:

Data obtained from the question include the following:

Molality of NaCl = 3.140 m

Mass of water = 2.692 kg

Mass of NaCl =.?

Next, we shall determine the number of mole of NaCl in the solution.

Molality is simply defined as the mole of solute per unit kilogram of solvent. Mathematically, it is expressed as

Molality = mole of solute /Kg of solvent

With the above formula, we can obtain the number of mole NaCl in the solution as follow:

Molality of NaCl = 3.140 m

Mass of water = 2.692 kg

Mole of NaCl =..?

Molality = mole of solute /Kg of solvent

3.140 = mole of NaCl /2.692

Cross multiply

Mole of NaCl = 3.140 x 2.692

Mole of NaCl = 8.45288 moles

Finally, we shall covert 8.45288 moles of NaCl to grams. This can be obtained as follow:

Mole of NaCl = 8.45288 moles

Molar mass of NaCl = 23 + 35.5 = 58.5 g/mol

Mass of NaCl =.?

Mole = mass /Molar mass

8.45288 = mass of NaCl /58.5

Cross multiply

Mass of NaCl = 8.45288 × 58.5

Mass of NaCl = 494.49 g.

Therefore, 494.49 g of NaCl are present in the solution.

8 0

3 years ago

PLEASE HELP!

fgiga [73]

150/30 = 5
HF1 20/2 = 10
HF2 10/2 = 5
HF3 5/2 = 2.5
HF4 2.5/2 = 1.25
HF5 1.25/2 = 0.625
Answer: 0.63g

5 0

2 years ago

Read 2 more answers

Which unit conversion allows you to convert 21.0 gallons into milliliters?

Ulleksa [173]

Answer:

Explanation:

we are given

there are in 0.073 gallons

we can see that there are two non-zero places after decimals

so, there are two siginificant figures

step-1: Change gallons to quarts

we know that

1 gallon = 4 quarts

so, we can write as

step-2: Change into liter

we know that

1 liter = 1.057 quarts

step-3: Change into millilitre

we know that

Since, it is asking for only two significant figures

so, we can also write as

...................Answer

3 0

2 years ago

_C4H6O3 + _H2O −−→ _C2H4O2 A) 1, 1, 2 B) 2, 1, 1 C) 2, 1, 2 D) 2, 2, 1

seraphim [82]

Explanation:

dredge to do with me to do with me to do with me to do with me to do with me to

8 0

2 years ago

This is the chemical formula for methyl acetate: CH32CO2. Calculate the mass percent of hydrogen in methyl acetate. Round your a

WITCHER [35]

Answer: The mass percent of hydrogen in methyl acetate is 8 %

Explanation:

The given chemical formula of methyl acetate is $CH_3COOCH_3$

To calculate the mass percentage of hydrogen in methyl acetate, we use the equation:

$\text{Mass percent of hydrogen}=\frac{\text{Mass of hydrogen}}{\text{Mass of methyl acetate}}\times 100$

Mass of hydrogen = (6 × 1) = 6 g

Mass of methyl acetate = [(3 × 12) + (6 × 1) + (2 × 16)] = 74 g

Putting values in above equation, we get:

$\text{Mass percent of hydrogen}=\frac{6g}{74g}\times 100=8.10\%=8\%$

Hence, the mass percent of hydrogen in methyl acetate is 8 %

8 0

3 years ago