A 0.500-g sample containing Na2CO3 plus inert matter is analyzed by adding 50.0 mL of 0.100 M HCl, a slight excess, boiling to remove CO2, and then back-titrating the excess acid with 0.100 M NaOH. If 5.6 mL NaOH is required for the back-titration, what is the percent Na2CO3 in the sample?

Answers

Answer 1

The percentage by mass of Na2CO3 in the sample is 48%.

The equation of the reaction of Na2CO3 with HCl;

Na2CO3(aq) + 2HCl(aq) ------> 2NaCl(aq) + H2O(l) + CO2(g)

Since the HCl is in excess, the excess is back titrated with NaOH as follows;

NaOH (aq) + HCl(aq) ---->NaCl(aq) + H2O(l)

Number of moles of HCl added =  0.100 M × 50/1000 L = 0.005 moles

Number of moles of NaOH added = 5.6/1000 ×  0.100 M = 0.00056 moles

Since the reaction of NaOH and NaOH is 1:1, 0.00056 moles of HCl reacted with excess HCl.

Amount of HCl that reacted with Na2CO3 =  0.005 moles -  0.00056 moles = 0.0044 moles

Now;

1 mole of Na2CO3 reacts with 2 moles of HCl

x moles of Na2CO3 reacts with 0.0044 moles of HCl

x = 1 mole × 0.0044 moles / 2 moles

x = 0.0022 moles

Mass of Na2CO3 reacted = 0.0022 moles × 106 g/mol = 0.24 g

Percentage of Na2CO3  in the sample = 0.24 g/ 0.500-g × 100/1 = 48%

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Earth

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Answer:

Earth

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What is the total pressure exerted by a mixture containing two gases if the partial pressure of one gas is 70 kPa and the partial pressure of the other gas is 30 kPa?

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Answer:

The total pressure of a mixture of gases can be defined as the sum of the pressures of each individual gas: Ptotal=P1+P2+… +Pn. + P n . The partial pressure of an individual gas is equal to the total pressure multiplied by the mole fraction of that gas.

Explanation:

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Answer:

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Explanation:

Answer:

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Would you expect a Boron (B) atom with atomic mass = 9.999 to be stable?

Answers

The balance of forces allows to find the result for the question if the isotope of boron 9.99 una  is stable:

The boron isotope of mass 9.99 uma is unstable because the repulsive force increases.

The stability of atomic nuclei depends on the balance the force is electrostatic repulsion between the protons and the strong interaction of attraction.

One way to achieve this balance is to increase the separation of the protons with uncharged particles between them, the neutral ones, the strong interaction is of the same magnitude for protons and neutrons, therefore the repulsion is decreased and the strong attraction interaction is maintained. .

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The boron isotope of mass 9.99 amu is unstable because the repulsive force increases.

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how do you Calculate the molarity of 250 ml of solution in which 2.7 g of MgCl2 are dissolved

Answers

Answer:

Molar mass of MgCl2 is 95 g/mol

Mg = 24 g/mol and Cl = 35.5 ×2 = 71 g/mol

moles = mass given/ molar mass

= 2.7/95 = 0.028 mol

volume = 250/1000 = 0.25 dm3 (ml is the same as dm3)

molarity of MgCl2 = moles/volume

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patient requires blood transfusion. what is the next thing to do? discuss​

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You have to find the blood type so you don’t cross contaminate

Which of the following best represents a ​chemical change?

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B. silver tarnishing

Which pair of elements form an ionic bond with
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B. ICL
C. PCL
D. HCL

I think it’s A and D but if it’s not both can you please explain why it’s one and not the other?

Answers

Answer:

Yes Both A) KCL and D) HCL are correct...

Answer:

It's only A

Explanation:

Potassium (K) is a metal and Chlorine (Cl) is a nonmetal, and ionic compounds are formed between metals and nonmetals. So KCl forms ionic bonds.

Hydrogen (H) and Chlorine (Cl) are both nonmetals, and only covalent bonds form between nonmetals. (Only exception is when its an acid, then it's ionic)

Also, the question indicated which "pair" and not "pairs" meaning that there is only one answer, and I'm more likely to go with A rather than D.

It takes 120 mL of 0.15 M of carbonic acid (H2CO3) to neutralize 300 mL of sodium hydroxide (NaOH) for the following balanced chemical reaction:

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Answers

First of all, you need to convert mL to L; 120mL = 0.12L, 300mL = 0.3L.

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If 2.5 moles of PA react completely, how many
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Answers

Answer:

For every 2 moles of Na used, 2 moles of NaCl are produced.

Explanation:

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Can someone help? Thank you.

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Answers

Answer: 50 M

Explanation:

Mass

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Answer:

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I’m a genius and it’s the answer :D

Biocompatibility is a challenge of prosthetic engineering that has been met through tissue engineering. Hence, option B is correct.

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Answer:

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Explanation:

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Polyvalent ions are

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Answer:
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Answers

1. The mass percentage of each element in aluminum oxide Al₂O are:

i. The mass percent of Al in Al₂O₃ is 52.9%

ii. The mass percent of O in Al₂O₃ is 47.1%

2. The mass of Al in 3.62 g of Al₂O₃ is 1.73 g

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Percentage of Al = (54 / 102) × 100

Percentage of Al = 52.9%

1ii. Determination of the percentage of O

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Answers

Answer:

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Answers

Answer:

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Answers

Answer:

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Explanation:

I hope it is fine answer for you ☺️☺️☺️

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Home lighting System is powered by solar energy using solar cells that convert solar energy (sunlight) directly to electricity. The electricity is stored in batteries and used for the purpose of lighting whenever required

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cyanoacrylate

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ehh im nit sure but here!

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50 PTS!!!!!
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Answer:

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Chemical  formula is a way of representing the number of atoms present in a compound or molecule.It is written with the help of symbols  of elements. It also makes use of brackets and subscripts.

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