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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will give brainliest and 100 points to the correct answer

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Answer:

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Explanation:

Answer:

2H2 + O2 → 2H2O

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Why does the Hubble Space Telescope take clearer pictures than other telescopes?

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Answer:

Space-based telescopes like Hubble get a much clearer view of the universe than most of their ground-based counterparts. ... Ground-based telescopes can't do the same, because the Earth's atmosphere absorbs a lot of the infrared and ultraviolet light that passes through it.

To calculate the atomic mass of an element, the percent
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Answer:

List the known and unknown quantities and plan the problem. Change each percent abundance into decimal form by dividing by 100. Multiply this value by the atomic mass of that isotope. Add together for each isotope to get the average atomic mass

Explanation:

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Answer:

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Which of the following is not part of an amino acid?
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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.

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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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It indicates that we have a Boron nucleus of mass 9.999. The number of protons must remain fixed, therefore there are only 4 neutrons.

Consequently, some of the protons does not have a neutron next to it and can approach the other proton, therefore the electrostatic repulsion increases and the stability of the atom decreases.

In conclusion, using the balance of Forces we can find the result for the question if the isotope of boron 9.99 una is stable:

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

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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?

Answers

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:

hope this helps have a wonderfull day!

Define Endothermic reaction in terms of Deta H

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I didn't learn about that topic in school,but I found this :

I hope it helps<3

Polyvalent ions are

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Answers

Answer:
3) Ions that can be positive or negative

Hope this helps!

increasing temperature increases:
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3:Entropy
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Answer:

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Explanation:

I hope it is fine answer for you ☺️☺️☺️

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Answer:

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Answer:

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Explanation:

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Which pair of elements form an ionic bond with
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Answers

Answer:

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

Answer:

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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.

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Answers

Answer:

C = 30

Explanation:

C = (86 - 32)/1.8

C = (54)/1.8

C = 30

50 PTS!!!!!
What type of chemical reaction is Aerobic Cellular Respiration?

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Answer: During aerobic respiration, catabolic reactions convert larger complex organic molecules into ATP, the chemical that drives most physiological processes in the body.

Explanation:

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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Answers

Answer:

ehh im nit sure but here!

Explanation:

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Answer:

Biocompatibility

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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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Hence, option B is correct.

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Which of the following best represents a ​chemical change?

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B. silver tarnishing

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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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1ii. Determination of the percentage of O

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Therefore,

3.62 g of Al₂O₃ will contain = (3.62 × 54) / 102 = 1.73 g of Al.

Thus, 1.73 g of Al is present in 3.62 g of Al₂O₃.

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Answer:

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Answers

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.

Subscripts are used to denote number of atoms of each element and brackets indicate presence of group of atoms. Chemical formula does not contain words. Chemical formula in the simplest form  is called empirical formula.

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What is the mass of an aluminum block if the density of aluminum is 2.70
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Answers

Answer: 50 M

Explanation:

Mass

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Formula used

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Can someone help? Thank you.

Answers

that' the answer i don't need an explanation

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Answers

sublimation- a change of state from a solid to a gas without going through the liquid state.

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melting- when a solid turns into a liquid

what are the solar home lighting​

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Answer:

Sunlight

Explanation:

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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Answers

The first image shown at the left hand side is a pi bond. The other two images show sigma bonds.

In chemistry, a bond results from the overlap of atomic orbitals. This overlap may be end to end (sigma bond) or side by side (pi bond). Having said this, it is easier to decide whether the bonds in the image shown are sigma or bi bonds.

If we label the images; 1,2,3 from left to right, we can see that the overlap in image 1 is side by side. The electron density lies above and below the plane of the bond. This is a pi bond. In images 2 and 3, the overlap occurs in an end to end manner. This is a sigma bond.

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Answer:B

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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
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