Answer:
[K₂CrO₄] → 8.1×10⁻⁵ M
Explanation:
First of all, you may know that if you dilute, molarity must decrease.
In the first solution we need to calculate the mmoles:
M = mmol/mL
mL . M = mmol
0.0027 mmol/mL . 3mL = 0.0081 mmoles
These mmoles of potassium chromate are in 3 mL but, it stays in 100 mL too.
New molarity is:
0.0081 mmoles / 100mL = 8.1×10⁻⁵ M
Explanation: This is a reaction of oxidation of
in the presence of acidified
. Acidified
is a strong oxidizing agent.
To balance out the
on the reactant side, we write
on the product side.
Balancing out the following reaction gives us:

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Answer:
- <em>The solution expected to contain the greatest number of solute particles is: </em><u>A) 1 L of 1.0 M NaCl</u>
Explanation:
The number of particles is calculated as:
a) <u>For Ionic compounds</u>:
- molarity × volume in liters × number of ions per unit formula.
b) <u>For covalent compounds</u>:
- molarity × volume in liters
The difference is a factor which is the number of particles resulting from the dissociation or ionization of one mole of the ionic compound.
So, calling M the molarity, you can write:
- # of particles = M × liters × factor
This table show the calculations for the four solutions from the list of choices:
Compound kind Particles in solution Molarity # of particles
(dissociation) (M) in 1 liter
A) NaCl ionic ions Na⁺ and Cl⁻ 1.0 1.0 × 1 × 2 = 2
B) NaCl ionic ions Na⁺ anc Cl⁻ 0.5 0.5 × 1 × 2 = 1
C) Glucose covalent molecules 0.5 0.5 × 1 × 1 = 0.5
D) Glucose covalent molecules 1.0 1.0 × 1 × 1 = 1
Therefore, the rank in increasing number of particles is for the list of solutions given is: C < B = D < A, which means that the solution expected to contain the greatest number of solute particles is the solution A) 1 L of 1.0 M NaCl.