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3 years ago

How many pints of a 30% sugar solution must be added to a 5 pint of a 5% sugar solution to obtain a 20% sugar solution?

Chemistry

1 answer:

ser-zykov [4K]3 years ago

5 0

You must add 7.5 pt of the 30 % sugar to the 5 % sugar to get a 20 % solution.

You can use a modified dilution formula to calculate the volume of 30 % sugar.

V_1×C_1 + V_2×C_2 = V_3×C_3

Let the volume of 30 % sugar = x pt. Then the volume of the final 20 % sugar = (5 + x ) pt

(x pt×30 % sugar) + (5 pt×5 % sugar) = (x + 5) pt × 20 % sugar

30x + 25 = 20x + 100

10x = 75

x = 75/10 = 7.5

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QUESTION 51 Buffer capacity is best defined as: OA) Buffer capacity is the amount of acid or base that can be added to a buffer

Schach [20]

Answer:

The best definition is: "Buffer capacity is the amount of acid or base that can be added to a buffer without destroying its effectiveness"

Explanation:

A buffer is a solution that is somewhat resist to pH changes by reacting with acids and bases that may be added into the solution. It's capacity is the amounto of acid or base that can be added into solution without much change in pH.

So the best definition is: "Buffer capacity is the amount of acid or base that can be added to a buffer without destroying its effectiveness"

4 0

3 years ago

What mass of calcium chloride is needed to prepare 2.657 L of a 1.56 M solution?

inna [77]

Answer:

459.126 grams of calcium chloride is needed to prepare 2.657 L of a 1.56 M solution

Explanation:

Molarity is a measure of the concentration of a solute in a solution that indicates the amount of moles of solute that appear dissolved in one liter of the mixture. In other words, molarity is the number of moles of solute that are dissolved in a given volume.

The Molarity of a solution is determined by the following expression:

$Molarity=\frac{number of moles of solute}{volume}$

Molarity is expressed in units $\frac{moles}{liter}$

In this case:

Molarity: 1.56 M= 1.56 $\frac{moles}{liter}$
Number of moles of calcium chlorine= ?
Volume= 2.657 liters

Replacing:

$1.56 M=\frac{Number of moles of calcium chlorine}{2.657 liters}$

Solving:

Number of moles of calcium chlorine= 1.56 M* 2.657 liters

Number of moles of calcium chlorine= 4.14 moles

In other side, you know:

Ca: 40 g/mole
Cl: 35.45 g/mole

Then the molar mass of the calcium chloride CaCl₂ is:

CaCl₂= 40 g/mole + 2* 35.45 g/mole= 110.9 g/mole

Now it is possible to apply the following rule of three: if in 1 mole there is 110.9 g of CaCl₂, in 4.14 moles of the compound how much mass is there?

$mass=\frac{4.14 moles*110.9g}{1 mole}$

mass= 459.126 g

459.126 grams of calcium chloride is needed to prepare 2.657 L of a 1.56 M solution

3 0

2 years ago

What is the molarity of the potassium hydroxide if 25.25 mL of KOH is required to neutralize 0.500 g of oxalic acid, H2C2O4? H2C

Greeley [361]

Answer:

0.444 mol/L

Explanation:

First step is to find the number of moles of oxalic acid.

n(oxalic acid) = $\frac{0.5g}{90.03 g/mol} = 5.5537*10^{-3} mol\\$

Now use the molar ratio to find how many moles of NaOH would be required to neutralize $5.5537*10^{-3} mol\\$ of oxalic acid.

n(oxalic acid): n(potassium hydroxide)

1 : 2 (we get this from the balanced equation)

$5.5537*10^{-3} mol\\$ : x

x = 0.0111 mol

Now to calculate what concentration of KOH that would be in 25 mL of water:

$c = \frac{number of moles}{volume} = \frac{0.0111}{0.025} = 0.444 mol/L$

5 0

3 years ago

gThe mole fraction of potassium nitrate in an aqueous solution is 0.0194. The solution's density is 1.0627 g/mL. What is the mol

xxMikexx [17]

Answer:

0.595 M

Explanation:

The number of moles of water in 1L = 1000g/18g/mol = 55.6 moles of water.

Mole fraction = number of moles of KNO3/number of moles of KNO3 + number of moles of water

0.0194 = x/x + 55.6

0.0194(x + 55.6) = x

0.0194x + 1.08 = x

x - 0.0194x = 1.08

0.9806x= 1.08

x= 1.08/0.9806

x= 1.1 moles of KNO3

Mole fraction of water= 55.6/1.1 + 55.6 = 0.981

xA= mole fraction of solvent

xB= mole fraction of solute

nA= number of moles of solvent

nB = number of moles of solute

MA= molar mass of solvent

MB = molar mass of solute

d= density of solution

Molarity = xBd × 1000/xAMA ×xBMB

Molarity= 0.0194 × 1.0627 × 1000/0.981 × 18 × 0.0194×101

Molarity= 20.6/34.6

Molarity of KNO3= 0.595 M

8 0

3 years ago

please hurry! If 3.87g of powdered aluminum oxide is placed in a container containing 5.67g of water, what is the limiting react

VikaD [51]

Answer:

Explanation:

Given parameters:

Mass of aluminium oxide = 3.87g

Mass of water = 5.67g

Unknown:

Limiting reactant = ?

Solution:

The limiting reactant is the reactant in short supply in a chemical reaction. We need to first write the chemical equation and convert the masses given to the number of moles.

Using the number of moles, we can ascertain the limiting reactants;

Al₂O₃ + 3H₂O → 2Al(OH)₃

Number of moles;

Number of moles = $\frac{mass}{molar mass}$

molar mass of Al₂O₃ = (2x27) + 3(16) = 102g/mole

number of moles = $\frac{3.87}{102}$ = 0.04mole

molar mass of H₂O = 2(1) + 16 = 18g/mole

number of moles = $\frac{5.67}{18}$ = 0.32mole

From the reaction equation;

1 mole of Al₂O₃ reacted with 3 moles of H₂O

0.04 mole of Al₂O₃ will react with 3 x 0.04 mole = 0.12 mole of H₂O

But we were given 0.32 mole of H₂O and this is in excess of amount required.

This shows that Al₂O₃ is the limiting reactant

6 0

2 years ago