Someone help me please!

A sucrose solution is prepared to a final concentration of 0.250 M . Convert this value into terms of g/L, molality, and mass %.

MArishka [77]

Answer:

A. 85.6 g

= 0.0856 kg.

B. 0.00027 mol/g

= 0.27 mol/kg.

C. 8.39 %

Explanation:

Given:

Molar concentration = 0.25 M

Molar weight of sucrose = 342.296 g/mol

Density of solution = 1.02 g/mL

Mass of water = 934.4 g.

Density in g/l = 1.020 g/ml * 1000ml/1 l

= 1020 g/l

Mass of solution in 1 l of solution = 1020 g

Mass of solution = mass of solvent + mass of solute

Mass of sucrose = 1020 - 934.4

= 85.6 g of sucrose in 1 l of solution.

A.

Density of sucrose = mass/volume

= molar mass/molar concentration

= 342.296 * 0.25

= 85.6 g/l

Number of moles = mass/molar mass

= 85.6/342.296

= 0.25 mol

B.

Molality = number of moles of solute/mass of solvent

= 0.25/934.4

= 0.00027 mol/g

C.

% mass of sucrose = mass of sucrose/total mass of solution * 100

= 85.6/1020 * 100

= 8.39 %

6 0

3 years ago

A 100.0 mL solution containing 0.864 g of maleic acid (MW=116.072 g/mol) is titrated with 0.276 M KOH. Calculate the pH of the s

Lilit [14]

Answer:

pH = 1.32

Explanation:

H₂M + KOH ------------------------ HM⁻ + H₂O + K⁺

This problem involves a weak diprotic acid which we can solve by realizing they amount to buffer solutions. In the first deprotonation if all the acid is not consumed we will have an equilibrium of a wak acid and its weak conjugate base. Lets see:

So first calculate the moles reacted and produced:

n H₂M = 0.864 g/mol x 1 mol/ 116.072 g = 0.074 mol H₂M

54 mL x 1L / 1000 mL x 0. 0.276 moles/L = 0.015 mol KOH

it is clear that the maleic acid will not be completely consumed, hence treat it as an equilibrium problem of a buffer solution.

moles H₂M left = 0.074 - 0.015 = 0.059

moles HM⁻ produced = 0.015

Using the Henderson - Hasselbach equation to solve for pH:

ph = pKₐ + log ( HM⁻/ HA) = 1.92 + log ( 0.015 / 0.059) = 1.325

Notes: In the HH equation we used the moles of the species since the volume is the same and they will cancel out in the quotient.

For polyprotic acids the second or third deprotonation contribution to the pH when there is still unreacted acid ( Maleic in this case) unreacted.

3 0

3 years ago

Problem PageQuestion Methane gas and chlorine gas react to form hydrogen chloride gas and carbon tetrachloride gas. What volume

IgorC [24]

Methane gas and chlorine gas react to form hydrogen chloride gas and carbon tetrachloride gas. What volume of hydrogen chloride would be produced by this reaction if 3.16 L of chlorine were consumed at STP.

Be sure your answer has the correct number of significant digits.

Answer: Thus volume of carbon tetrachloride that would be produced is 0.788 L

Explanation:

According to ideal gas equation:

$PV=nRT$

P = pressure of gas = 1 atm (at STP)

V = Volume of gas = 3.16 L

n = number of moles = ?

R = gas constant = $0.0821Latm/Kmol$

T =temperature = $273K=$

$n=\frac{PV}{RT}$

$n=\frac{1atm\times 3.16L}{0.0820 L atm/K mol\times 273K}=0.141moles$

$CH_4+4Cl_2\rightarrow 4HCl+CCl_4$

According to stoichiometry:

4 moles of chlorine produces = 1 mole of carbon tetrachloride

Thus 0.141 moles of methane produces = $\frac{1}{4}\times 0.141=0.0352$ moles of carbon tetrachloride

volume of carbon tetrachloride = $moles\times {\text {Molar volume}}=0.0352mol\times 22.4L/mol=0.788L$

Thus volume of carbon tetrachloride that would be produced is 0.788 L

8 0

4 years ago

For each chemical equation below, write the number of product molecules that will form from the reaction.

Gekata [30.6K]

Answer:

a. 5 moles of CO₂

b. 2 moles of NaCl

c. 3 moles of H₂CO₃

Explanation:

1a. Carbon reacts with oxygen to produce carbon dioxide according to equation below:

C + O₂ ----> CO₂

From the equation of reaction, one mole of carbon reacts with one mole of oxygen to produce one mole of carbon dioxide.

In the given reaction, therefore, 5 moles of carbon will only react with 5 moles of oxygen to produce 5 moles of carbon dioxide. Oxygen is in excess, carbon is the limiting reactant and 5 moles of carbon dioxide are produced. The equation is given below :

5 C + 6 O₂ ---> 5 CO₂

1b. Sodium reacts with chlorine to produce sodium chloride according to the equation below:

2 Na + Cl₂ ---> NaCl

From the equation of reaction, 2 moles of sodium reacts with one mole of chlorine to produce one mole of sodium chloride.

In the given reaction, therefore, 4 moles of sodium will react with only 2 moles of chlorine to produce 2 moles of sodium chloride. Chlorine is in excess, sodium is the limiting reactant and 2 moles of sodium chloride are produced. The equation is given as follows: 4 Na + 8 Cl₂ ---> 2 NaCl

1c. Carbon dioxide reacts with water to produce carbonic acid according to the equation: CO₂ + H₂O ---> H₂CO₃

From the equation of reaction one mole of carbon dioxide reacts with one mole of water to produce one mole of carbonic acid.

In the given reaction, therefore, 3 moles of carbon dioxide will react with only 3 moles of water to produce 3 moles of carbonic acid. Water is in excess, carbon dioxide is the limiting reactant and 3 moles of carbonic acid are produced. The equation is given as follows: 3 CO₂ + 4 H₂O ---> 3 H₂CO₃

4 0

3 years ago

LAST TIME, I WILL AWARD BRAINLIEST TO WHOEVER ANSWERS ALL THE QUESTIONS RIGHT!!!!

Anika [276]

Answer: Millard Reaction

Explanation:The yummy process, called the Maillard reaction, packs the cookie with riche taste

3 0

3 years ago