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3 years ago

Which of the following is true when 1 M KCl is diluted to semi-molar KCl?

Chemistry

1 answer:

eimsori [14]3 years ago

4 0

The solution before dilution and after dilution contains same number of moles, and water is added for dilution.

Option B

<h3><u>Explanation:</u></h3>

Suppose before dilution, the solution contains x moles of KCl in Y liter of water. Now as the concentration got halved, then the solution contains x moles of KCl in 2Y kiters of solution. So the number of moles of KCl in the solution remained constant.

Again, as the solution is diluted to half of the concentration, water must have been added with the solution to make it dilute.

You might be interested in

What characteristic of rivers at their source gives them so much power to shape the land

Zielflug [23.3K]

River sources tend to be at the top of mountains or areas of high elevation. This means that rivers impact the entire terrain from mountains to seas and oceans.

I hope this Helps!

8 0

3 years ago

If 12.5 grams of strontium hydroxide is reacted with 150 mL of 3.5 M carbonic acid, identify the limiting reactant.

kiruha [24]

Answer:

Sr(OH)₂ will be the limiting reagent.

Explanation:

First of all, you should know the following balanced chemical equation:

2 H₂CO₃ + 2 Sr(OH)₂ → 4 H₂O + Sr₂(CO₃)₂

The balanced equation is based on the Law of Conservation of Mass, which says that matter cannot be created or destroyed. Therefore, the number of each type of atom on each side of a chemical equation must be the same.

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

To determine the limiting reagent, it is possible to use the reaction stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction). By stoichiometry the following amounts in moles react:

strontium hydroxide: 2 moles
carbonic acid: 2 moles

Now, you know the following masses of the elements:

Sr: 87.62 g/mole
O: 16 g/mole
H: 1 g/mole

So the molar mass of strontium hydroxide is:

Sr(OH)₂= 87.62 g/mole + 2*(16 g/mole + 1 g/mole)= 121.62 g/mole

You apply the following rule of three, if 121.62 grams of hydroxide are present in 1 mole, 12.5 grams in how many moles are they?

$moles of strontium hydroxide=\frac{12.5 grams*1 mole}{121.62 grams}$

moles of hydroxide= 0.103 moles

On the other hand, you have 150 ml of 3.5 M carbonic acid. Since molarity is the concentration of a solution expressed in the number of moles dissolved per liter of solution, you can apply the following rule of three: if in 1 L there are 3.5 moles of carbonic acid, in 0.150 L (being 1 L = 1000 mL, 0.150 L = 150 mL) how many moles of acid are there?

$molesofcarbonicacid=\frac{0.150 L*3.5 moles}{1 L}$

moles of carbonic acid= 0.525 moles

Finally, to calculate the limiting reagent, you can use a simple rule of three as follows: if by stoichiometry 2 mole of strontium hydroxide reacts with , how much moles of carbonic acid will be needed if 0.103 moles of strontium hydroxide react?

$molesofcarbonicacid=\frac{0.103 moles of strontium hydroxide*2 moles of carbonic acid}{2 moles of strontium hydroxide}$

moles of carbonic acid= 0.103 moles

But 0.525 moles are available. Since more moles are available than you need to react with 0.103 moles of strontium hydroxide, <u><em>Sr(OH)₂ will be the limiting reagent.</em></u>

7 0

3 years ago

LICUICY NICULUM

Evgen [1.6K]

Answer:

Missing component

Cl₂

H₂O

Explanation:

Reaction given:

? + 2NaBr → 2NaCl+Br

Mg+? → MgO+H2

missing component = ?

Solution:

Reaction 1

? + 2NaBr -----→ 2NaCl + Br

if we look at the reactants and products there is one element is in product side but not shown in the reactant side.

In products there are following atoms

Na (Sodium)

Cl (Chlorine)

Br (Bromine)

In Reactant there are following atoms

Na (Sodium)

Br (Bromine)

So only Chlorine is missing in the reactant side.

if we put chlorine in the reactant then this reaction will be complete

Cl + 2 NaBr -----→ 2NaCl + Br

So chlorine react with water and give sodium chloride and bromine molecule, this is a single displacement reaction and chlorine replace bromine in the above reaction

Now balance the equation

Cl₂ + 2 NaBr -----→ 2NaCl + Br₂

So, the missing component is

Cl₂

____________

Reaction 2

Mg + ? ---------→ MgO + H₂

if we look at the reactants and products there are two element in product side but not shown in the reactant side.

In products there are following atoms

Mg (Magnesium)

O (Oxygen)

H (Hydrogen)

In Reactant there is only one following atom

Mg (Magnesium)

So Oxygen and Hydrogen is missing in the reactant side.

if we put water molecule (H₂O) in the reactant then this reaction will be complete

Mg + H₂O ---------→ MgO + H₂

in this reaction magnesium (Mg) react with water (H₂O) and give magnesium oxide and hydrogen gas.

So, the missing component is

H₂O

3 0

3 years ago

Read 2 more answers

Plz help well mark brainliest if correct!!

USPshnik [31]

Answer:

the hole in Earth was caused by a meteorite

6 0

2 years ago

A mixture is made by combining 1.49 lb of salt and 3.82 lb of water.

Pavel [41]

Answer:

28%

Explanation:

concentration=(solute mass/solution mass)*100

C=concentration

md-solute mass

ms-solution mass

the solution mass is equal to the sum of the solute and solvent mass

ms=3.82+1.49=5.31lb

c=1.49/5.31 * 100=0.28*100=28%

7 0

3 years ago