Sponges, Cnidarians, Flatworms, and Roundworms are all in which group of animals?

A 5.000 g mixture contains strontium nitrate and potassium bromide. Excess lead(II) nitrate solution is added to precipitate out

scZoUnD [109]

Answer: The mass percent of potassium bromide in the mixture is 9.996%

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For lead (II) bromide:

Given mass of lead (II) bromide = 0.7822 g

Molar mass of lead (II) bromide = 367 g/mol

Putting values in equation 1, we get:

$\text{Moles of lead (II) bromide}=\frac{0.7822g}{367g/mol}=0.0021mol$

The chemical equation for the reaction of lead (II) nitrate and potassium bromide follows:

$2KBr+Pb(NO_3)_2\rightarrow PbBr_2+2KNO_3$

By Stoichiometry of the reaction:

1 mole of lead (II) bromide is produced from 2 moles of potassium bromide

So, 0.0021 moles of lead (II) bromide will be produced from = $\frac{2}{1}\times 0.0021=0.0042mol$ of potassium bromide

Now, calculating the mass of potassium bromide by using equation 1, we get:

Molar mass of KBr = 119 g/mol

Moles of KBr = 0.0042 moles

Putting values in equation 1, we get:

$0.0042mol=\frac{\text{Mass of KBr}}{119g/mol}\\\\\text{Mass of KBr}=0.4998g$

To calculate the percentage composition of KBr in the mixture, we use the equation:

$\%\text{ composition of KBr}=\frac{\text{Mass of KBr}}{\text{Mass of mixture}}\times 100$

Mass of mixture = 5.000 g

Mass of KBr = 0.4998 g

Putting values in above equation, we get:

$\%\text{ composition of KBr}=\frac{0.4998g}{5.000g}\times 100=9.996\%$

Hence, the percent by mass of KBr in the mixture is 9.996 %

5 0

3 years ago

Why don’t scientists use the Bohr model above to explain charge transfer?

Jlenok [28]

Answer:

nsksbsjensnsjeiejensbsksks

3 0

3 years ago

Please help me with this question please!!!

Deffense [45]

Answer:

A

Explanation:

I looked up aromatic hydrocarbon and this one looks like a replica of benzene

3 0

3 years ago

Why is it important that there is only a small amount of water in the beaker

natita [175]

Answer:

because too much can neutralise the results

4 0

3 years ago

Read 2 more answers

Two different compounds are obtained by combining nitrogen with oxygen. the first compound results from combining 46.7 g of n wi

kondaur [170]

First:

46.7 g of N with 53.3 g of O,

=> mass ratio O to N = 53.3 / 46.7 = 1.1413

Second

17.9 g of N and 82.0 g of O.

mass ratio of O to N = 82.0 / 17.9 = 4.5810

Third

Ratio of the mass ratio of O to N in the second compound to the mass ratio of O to N in the first compound =

= 4.5810 / 1.1413 = 4.013 ≈ 4

Answer: 4

8 0

3 years ago