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alexgriva [62]
2 years ago
8

Washing soda is a hydrate of sodium carbonate. Elemental analysis of a sample of washing soda gave 4.20% C and 7.05% H. What is

the formula for washing soda?
Chemistry
1 answer:
kozerog [31]2 years ago
5 0

Answer:

Na₂CO₃ · 10H₂O

Explanation:

The formula for sodium carbonate hydrate is:

Na₂CO₃ · xH₂O

The unknown "x" is the number of water molecules contained in the hydrate.

To find "x" we have to use the hydrogen percentage in the sample, 7.05 % H.

First we calculate the molecular weight of Na₂CO₃ · xH₂O:

molecular weight of Na₂CO₃ · xH₂O = 23 × 2 + 12 + 16 × 3 + 18x

molecular weight of Na₂CO₃ · xH₂O = 106 + 18x  g/mole

Now we devise the fallowing reasoning tanking in account 1 mole of Na₂CO₃ · xH₂O:

if in        106 + 18x grams of Na₂CO₃ · xH₂O we have 2x grams of hydrogen

then in  100 grams of Na₂CO₃ · xH₂O we have 7.05 grams of hydrogen

106 + 18x = (100 × 2x) / 7.05

106 + 18x = 28.4x

106 = 28.4x - 18x

106 = 10.4x

x = 106 / 10.4

x = 10.2 ≈ 10

The formula for the washing soda is Na₂CO₃ · 10H₂O.

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The atom has only one isotope which means 100 % of same atom is present in nature. The atomic mass of an element is the number of times an atom of that element is heavier than an atom of carbon taken as 12. Mass of one atom of that isotope is 9.123 ✕ 10⁻²³ g, so mass of one mole of atom that is Avogadro's number of atom is 6.023 X 10²³  X 9.123 X 10⁻²³ g=54.94 g = 55 g (approximate).

So, the atom having atomic mass 55 will be Cesium (Cs). Only one isotope of Cesium is stable in nature.

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After passing through pyruvate dehydrogenase and the citric acid cycle, one mole of pyruvate will result in the formation of ___
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The answer to be filled in the respective blanks in question is

3 and 1

Explanation:

So, we know that the formation of cabon-dioxide mole and that of Adenosin-Tri-Phosphate (ATP) moles will be in the ratio of 3:1 i.e., three carbon-di-oxide moles and 1 ATP mole.

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2 years ago
How much heat is required to raise the temperature of 670g of water from 25.7"C to 66,0°C? The specific heat
inna [77]

Answer:

Explanation:

q= mc theta

where,

Q = heat gained

m = mass of the substance = 670g

c = heat capacity of water= 4.1 J/g°C    

theta =Change in temperature=( 66-25.7)

Now put all the given values in the above formula, we get the amount of heat needed.

q= mctheta

q=670*4.1*(66-25.7)

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Consider a beaker of water sitting on the pan of an electronic scale that has been tared. A metal weight hanging from a string i
natka813 [3]

Answer:

See explanation below for answers

Explanation:

We know that the balance is tared, so the innitial weight would be zero. Now, let's answer this by parts.

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In this case, we have the density of water, so we use the formula for density and solve for volume:

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