How many Br atoms are in 1.98 g of Br?
1 answer:
Answer:
1.5 x 10²²atoms
Explanation:
Given parameters:
Mass of Br = 1.98g
Unknown:
Number of atoms
Solution:
A mole of a substance is the amount of substance contained in the avogadro's number of particles.
To solve this problem, we must first find the number of moles present in the given mass of the Br atom:
Number of moles = =
= 0.025mole.
Now we know that:
1 mole = 6.02 x 10²³
0.025 mole = 0.025 x 6.02 x 10²³ = 1.5 x 10²²atoms
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Explanation:
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Answer : The resulting concentrations of CV and NaOH are 0.0027 M and 0.025 M respectively.
Explanation :
Step 1 : Find moles of crystal violet and NaOH.
The molarity formula is
Molarity of crystal violet =
The volume of crystal violet solution is 18 mL which is 0.018 L.
Moles of crystal violet =
Moles of crystal violet = 5.4 x 10⁻⁵
Moles of NaOH =
Moles of NaOH = 5.00 x 10⁻⁴
Step 2 : Find total volume of the solution
The total volume of the solution after mixing NaOH and crystal violet is
0.018 L + 0.00200 = 0.020 L
Step 3 : Use molarity formula to find final concentrations
Molarity of crystal violet =
Final concentration of CV = 0.0027 M
Molarity of NaOH=
NaOH is a strong base and dissociates completely as follows.
The mole ratio of NaOH and OH⁻ is 1:1 . Therefore the concentration of OH⁻ is same as that of NaOH.
Concentration of OH⁻ = 0.025 M