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3 years ago

What does the mole ratio represent

Chemistry

1 answer:

Drupady [299]3 years ago

3 0

Answer:

A mole ratio is a conversion factor that relates the amounts in moles of any two substances in a chemical reaction

Explanation:

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Consider the titration of 100.0 mL of 0.100 M acetic acid with 0.100 M NaOH. CH3CO2H(aq) + OH-(aq) → CH3CO2-(aq) + H2O(ℓ) Ka for

allsm [11]

Answer:

a) pH = 5.70

b) pH = 8.22

c)pH = 11.68

Explanation:

a)NaOH (aq)+CH3COOH(aq) ------> CH3COONa(aq) + H2O(aq)

1mol of NaOH react with 1mol of CH3COOH

No of mole in 90ml of 0.1M NaOH

= (0.1mol/1000ml)×90ml

= 0.009

No of mol in 100ml of CH3COOH

= (0.1/1000)×100

= 0.01

No of mol of CH3COOH after addition

= 0.01-0.009

= 0.001

Total volume = 100ml + 90ml

= 190ml

Final molarity of CH3COOH =( 0.0025/190) ×1000

= 0.00526M

Concentration of CH3COONa formed =( 0.0075/190) ×1000

= 0.0474M

Ka of CH3COOH = 1.8 × 10^-5

pka = -log(ka)

pKa = 4.75

Applying Henderson equation

pH = pKa + log ( [A-]/[HA])

pH = 4.75 + log ( 0.0474/0.00526)

= 5.70

At equivalencepoint point ,

No of moles of CH3COOH = 0

No of moles of CH3COO- = 0.01 mol

Total volume = 200ml

molarity of CH3COO- = 0.01/2

= 0.0050M

CH3COO- (aq) + H2O(l) <---------> CH3COOH(aq) + OH-(aq)

Kb = [ CH3COOH] [ OH- ] / [ CH3COO- ]

= 1.8 × 10^-5

[ CH3COOH ] = X

[ OH-] = X

[ CH3COO-] = 0.0050 - X

5.6 × 10^-10 = X^2/ (0.0050 - X)

we can assume , 0.0050 - X = 0.0050

5.6 × 10^-10 = X^2/0.0050

X = 1.67 × 10^6

[OH-] = 1.67 × 10^-6

pOH = 5.78

pH = 14 - pOH

pH = 14 -5.78

pH = 8.22

c) No of mol of OH from excess 10ml of NaOH = (0.1mol /1000ml)×10ml = 0.001mol

No of mol of OH- from hydrolysis of CH3COO- = (1.67×10^-6/1000)×200= 3.34×10^-7mol

Second one is negligible

So, no of mol OH- = 0.001mol

Total volume = 100ml + 110ml

= 210ml

[OH-] =( 0.001/210)×1000

= 0.0048M

pOH = -log[OH-]

= - log (0.0048)

= 2.32

pH = 14 - 2.32

pH = 11.68

4 0

3 years ago

Desperate pldease hurry Why aren’t fuel-cell vehicles widely available yet?

Vaselesa [24]

Answer:

There's virtually no pure hydrogen on Earth because it's so reactive. Most hydrogen is made from methane [natural gas] in a process that produces carbon dioxide and other greenhouse gases. Hydrogen can also be made from water using electrolysis, but that requires electrical energy.

Explanation:

6 0

2 years ago

Read 2 more answers

What is the fraction of the hydrogen atom's mass (11h) that is in the nucleus? the mass of proton is 1.007276 u, and the mass of

ololo11 [35]

Hello there!

To determine the fraction of the hydrogen atom's mass that is in the nucleus, we have to keep in mind that a Hydrogen atom has 1 proton and 1 electron. Protons are in the nucleus while electrons are in electron shells surrounding the nucleus. The mass of the nucleus will be equal to the mass of 1 proton and we can express the fraction as follows:

$Mass Fraction= \frac{mass 1 Proton}{mass H atom} = \frac{1,007276 u}{1,007825}=0,9995$

So, the fraction of the hydrogen atom's mass that is in the nucleus is 0,9995. That means that almost all the mass of this atom is at the nucleus.

Have a nice day!

3 0

3 years ago

How many molecules of sodium oxide will be created if 187 grams of oxygen reacts with excess sodium? 4Na + O2 -> 2Na2O A. 11.

Jet001 [13]

Answer:

7.04 × 10²⁴ molecules of Na₂O

Explanation:

1) Balanced chemical equation (given):

4 Na(s) + O₂ (g) → 2Na₂O (s)

2) Mole ratio:

1 mol O₂ : 2 mol Na₂O

3) Number of moles of O₂ in 187 grams of oxygen:

Molar mass O₂ = 32.00 g/mol

Number of moles = mass in grams / molar mass = 187 g / 32.00 g/mol = 5.844 mol

4) Number of moles of Na₂O:

Proportion: 1 mol O₂ / 2 mol Na₂O = 5.844 mol O₂ / x

x = 5.844 mol O₂ (2 mol Na₂O / 1 mol O₂) = 11.688 mol Na₂O

5) Number of molecules

Number of molecules = number of moles × Avogadro's number

Number of molecules = 11.688 mol × 6.022 × 10²³ molecules/mol =

= 7.04 × 10 ²⁴ molecules ← answer

The answer is rounded to three significant figures.

4 0

3 years ago

O2 would not be considered as a compound. True False

MissTica

True, a compound consists of two different molecules/atoms

4 0

4 years ago