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Chemistry 9 Online
Jaynator495:

Chem help

Jaynator495:

@JustSaiyan

JustSaiyan:

Alright.

Jaynator495:

Just hang on - Just finding it LOL

Jaynator495:

1. Determine the percent composition of the following compounds: a. CuBr2 b. N2S2

JustSaiyan:

A: Cu: 28.45% Br: 71.55%

Jaynator495:

Please show the full calculations on how you got that answer :)

JustSaiyan:

Alright.

JustSaiyan:

first determine the mass of each element

JustSaiyan:

Count the number of hydrogens

JustSaiyan:

Then, divide the elements to get the percent.

Jaynator495:

Alrighty, can you apply that into numbers now? :P m = mass h = hydrogen's m/h?

JustSaiyan:

1(63.546) + 2(79.904) = 223.354 63.546/223.354) X 100 = 28 Cu = 28% {2(79.904) / 223.354} X 100 = 71.5 Br271.5% That is A.

Jaynator495:

Br2 = 71.5% or Br271.5%? ._.

JustSaiyan:

Br2 = 71.5%

Jaynator495:

*stare*

Jaynator495:

You've been typing a reply for a awefully long time

Jaynator495:

Determine the percent composition from the following analytical data: a. An experiment was performed in which 6.1 g table salt produced 2.6 g Cl in the sample. b. A reaction uses 18.06 grams Mg to react completely with 6.96 grams N

JustSaiyan:

\[2 N atoms × \frac{ 14.01u }{ 1~n~atom } = 28.02 u.\] \[ 2 S atoms × \frac{ 32.06u }{ 1~s~atom } = 64.12\] \[\frac{ mass~of~N }{ total~mass } \times 100 % = \frac{ 28.02u }{ 92.14u } × 100 % =30.41 %\] \[\frac{ mass~of~S }{ total~mass } \times 100 % = \frac{ 64.12u }{ 92.14u } × 100 % =69.59 %\]

JustSaiyan:

Are you kidding. hold on. the last 2 ***ed up at the percent mark.

Jaynator495:

Ok o-o

JustSaiyan:

\[\frac{ 28.02 u }{ 92.14 u } × 100~percent =30.41~percent\] End of ***ed up line one. \[\frac{ 64.12 u }{ 92.14 u } × 100~percent =69.59~percent\] End of ***ed up line 2

JustSaiyan:

Remember these are finishing the bottom to on the previous one that I said I ***ed up.

JustSaiyan:

Damn that was a pain in the ***.

JustSaiyan:

Is that all?

Jaynator495:

nope

Jaynator495:

What is a hydrate?

JustSaiyan:

a substance that contains water or part of its elements.

Jaynator495:

Calculate the percent by mass of water in the following compounds: a. FeCl3⋅6H2O b. Ba(OH)2⋅8H2O

JustSaiyan:

A. Fe: 1 x 55.8 = 55.8 Cl: 3 x 35.45 = 106.4 H: 12 x 1.0 = 12.0 O: 6 x 16 = 96.0 The total is 270.2 g/mol. % H2O = (108/270.2) x 100 = 40.0%

JustSaiyan:

B. Ba(OH)2 * 8 H2O = 315.46 g /mol molar mass H2O = 18.02 g/mol % water = 8 x 18.02 x 100/ 315.46 = 45.7

Jaynator495:

Calculate the empirical formula of each compound from the data listed below: a) 65.5% C, 5.5% H, 29.0% O b) 34.95% C, 6.844% H, 46.56% O, 13.59% N

JustSaiyan:

the 65.5 g is carbon 5.5 g in hydrogen and 29 grams is oxygen C = 12.011 g/mole H = 1.0079 g/mole O = 15.9994 g/mole moles C = 65.5g * mole/12.011g = 5.4533 moles moles H = 5.5g * mole/1.0079 g = 5.4569 moles moles O = 29g * mole/15.9994g = 1.8126 moles divide by the lowest (Oxygen) C = 5.4533/1.8126 = 3 H = 5.4569/1.8126 = 3 C = 1 Empirical formula = C3H3O MW = 55.0561 g/mole

JustSaiyan:

Find the number of moles of each substance C = 34.95 / 12 = 2.9125 H = 6.844/1 = 6.844 O = 46.56/16 = 2.91 N = 13.59/14 = 0.9707 Now you take the smallest number and divide into all the others, but including itself. C = 2.9125/0.9707 = 3 H = 6.844 / 0.9707 = 7 O = 3 (same as the carbon N = 1 The empirical formula = C3 H7 O3 N

JustSaiyan:

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