1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
KatRina [158]
3 years ago
15

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

0.7822 grams of lead(II) bromide. What is the percent by mass of potassium bromide in the mixture?
Chemistry
1 answer:
scZoUnD [109]3 years ago
5 0

<u>Answer:</u> The mass percent of potassium bromide in the mixture is 9.996%

<u>Explanation:</u>

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

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

<u>For lead (II) bromide:</u>

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 %

You might be interested in
A sample of a uranium compound is found to be losing mass gradually. Explain what is happening to the sample.
irina [24]

Explanation:

Uranium have an unstable nuclei , hence it  is a radioactive element , and radioactive element can undergo radioactive decay like the alpha decay , beta decay .

Radioactive decay is a spontaneous breakdown of the atomic nucleus which , results in the release of energy along with radioactive particles , like alpha , beta , gamma etc .

Hence ,

The mass is lost from a sample of uranium .

3 0
3 years ago
When a scientist is beginning the process what is the key term she or he must ask in order to begin?
ella [17]

Answer:

B- why or how because any scientist deals with matter it's relationships ,properties and its composition which can be inferred from the questions why and how

5 0
2 years ago
hat is the product when magnesium reacts with nitrogen? Mg(s) + N2(g) → Mg2N3(s) Mg3N(s) Mg3N2(s) MgN3(s)
Ipatiy [6.2K]
3Mg + N₂ = Mg₃N₂

Mg₃N₂
______________________
5 0
3 years ago
Read 2 more answers
You have 5 cars and you double that amount.How much cars do you have.
Nostrana [21]

Answer:

10 cars

Explanation:

the double of 5 is 10

5+5=10

5 0
2 years ago
What changes if the degree (amount) of intermolecular bonds of a substance are changed?
elixir [45]
<h2>Answer:</h2>

The correct answers are;

volume of a substance

density of a substance

  • The volume and the density of the substance depend on inter molecular forces of the substance. So, when we will change the degree of inter molecular forces, whether decrease it or increase it, it will affect the volume and density of a substance.
7 0
3 years ago
Read 2 more answers
Other questions:
  • How many electrons can be held in the second orbital (closest to the nucleus)
    7·2 answers
  • Spread Spectrum (SS) encoding: a) Name four spread spectrum techniques. b) Which one of them was originally devised against eave
    9·1 answer
  • A speed-time graph shows a line sloping downward. How was the speed changing?
    11·1 answer
  • High-purity benzoic acid (C6H5COOH; ΔHrxn for combustion = −3227 kJ/mol) is used as a standard for calibrating bomb calorimeters
    5·1 answer
  • if 200.0 of copper (II) sulfate react with an excess of zinc metal, what is the theoretical yield of copper?
    12·1 answer
  • Which profile best shows the topography alone line AD
    7·1 answer
  • How many elements are in P4I10
    10·1 answer
  • LOTS OF POINTS (75) I WILL GIVE BRAINLIEST!!!!!
    6·1 answer
  • The limiting reactant in a chemical reaction is the reactant __________ Select one: A. for which you have the lowest mass in gra
    13·1 answer
  • During a lab exam a student looked through the microscope and identified the following cell parts: circular DNA, ribosomes, cell
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!