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3 years ago

What are the molality and mole fraction of solute in a 22.3 percent by mass aqueous solution of formic acid (HCOOH)?

Chemistry

2 answers:

romanna [79]3 years ago

7 0

Answer:

Molality = 6.23 molal

Mol fraction HCOOH = 0.101

Explanation:

Step 1: Data given

mass % of HCOOH = 22.3 %

Step 2: Calculate mass

22.3 % means we have 22.3 grams HCOOH in 100 gram solution

Mass of water = 100 grams - 22.3 grams = 77.7 grams

Step 3: Calculate moles

Moles HCOOH = mass HCOOH / molar mass HCOOH

Moles HCOOH = 22.3 grams / 46.03 g/mol

Moles HCOOH = 0.484 moles

Moles H2O = 77.7 grams / 18.02 g/mol

Moles H2O = 4.31 moles

Step 4: Calculate molality

Molality = moles HCOOH / mass H2O

Molality = 0.484 moles / 0.0777 kg

Molality = 6.23 molal

Step 5: Calculate mol fraction

Mol fraction HCOOH = mole HCOOH / total moles

Mol fraction HCOOH = 0.484 moles / (4.31+0.484)moles

Mol fraction HCOOH = 0.101

Vanyuwa [196]3 years ago

6 0

Answer:

Mole fraction for solute = 0.1, or 10%

Molality = 6.24 mol/kg

Explanation:

22.3% by mass → In 100 g of solution, we have 22.3 g of HCOOH

Mass of solution = 100 g

Mass of solute = 22.3 g

Mass of solvent = 100 g - 22.3g = 77.7 g

Let's convert the mass to moles

22.3 g . 1mol/ 46 g = 0.485 moles

77.7 g. 1mol / 18 g = 4.32 moles

Total moles = 4.32 moles + 0.485 moles = 4.805 moles

Xm for solute = 0.485 / 4.805 = 0.100 → 10%

Molality → mol/ kg → we convert the mass of solvent to kg

77.7 g. 1 kg / 1000g = 0.0777 kg

0.485 mol / 0.0777 kg = 6.24 m

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zhannawk [14.2K]

Answer:

Option (D)

Explanation:

Weathering is usually defined as the disintegration of rocks at the surface of the earth. This break down of rocks is mainly caused by the geological processes that occur on the earth's surface. This process results in the formation of sediments that are transported and deposited in a new environment.

This weathering process primarily takes place in three different ways such as-

Physical weathering- Here, the rocks are broken down by the physical agents such as wind, water, ice.

Chemical weathering- Here the rocks are broken down when interacts with the chemical containing water.

Biological weathering- here, the rocks are broken down due to the activities done by organisms such as plants and animals.

In the given condition, Quincy can see a real example of rock weathering in the high mountainous region, as in the mountainous region the rocks are frequently weathered and eroded by the agents such as wind, water, and ice.

Thus, the correct answer is option (D).

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3 years ago

25. How many ml of a .0023M strontium hydroxide solution are needed to completely react 15.0 mL of 0.012M hydrochloric acid?

Mariana [72]

Answer: There are 78.26 mL of a 0.0023M strontium hydroxide solution are needed to completely react 15.0 mL of 0.012M hydrochloric acid.

Explanation:

Given: $M_{1}$ = 0.0023 M, $V_{1}$ = ?

$V_{2}$ = 15.0 mL, $M_{2}$ = 0.012 M

Formula used to calculate volume of strontium hydroxide solution is as follows.

$M_{1}V_{1} = M_{2}V_{2}$

Substitute the values into above formula as follows.

$M_{1}V_{1} = M_{2}V_{2}\\0.0023 M \times V_{1} = 0.012 M \times 15.0 mL\\V_{1} = 78.26 mL$

Thus, we can conclude that there are 78.26 mL of a 0.0023M strontium hydroxide solution are needed to completely react 15.0 mL of 0.012M hydrochloric acid.

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3 years ago

In the single displacement reaction of HCl and magnesium, how many grams of magnesium chloride would be produced if 1.05g of mag

iren [92.7K]

Answer:

4.16g of MgCl2

Explanation:

First, let us generate a balanced equation for the reaction:

Mg + 2HCl —> MgCl2 + H2

Molar Mass of Mg = 24g/mol

Molar Mass of MgCl2 = 24 + (2x35.5) = 24 + 71 = 95g

From the equation,

24g of Mg produced 95g of MgCl2.

Therefore, 1.05g of Mg will produce = (1.05x95)/24 = 4.16g of MgCl2

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3 years ago

Who arranged the elements according to atomic mass and used the arrangement to predict the properties of missing element?

Marina CMI [18]

Answer:

Dmitri Mendeleev

Explanation:

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Dmitri Mendeleev around 1869 described the periodic table.
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