Answer: In order to forecast the weather, they study high and low pressure systems and the boundaries between them which is why they are called weather fonts
Explanation:
The question is incomplete; the complete question is;
A chemist must dilute 99.4 mL of 152 mM aqueous potassium dichromate (K_2Cr_2O_7) solution until the concentration falls to 55.0 mM He'll do this by adding distilled water to the solution until it reaches a certain final volume. Calculate this final volume, in liters. Be sure your answer has the correct number of significant digits.
Answer:
0.275 L
Explanation:
From C1V1 = C2V2
Where;
C1= initial concentration of the solution 152 × 10^-3 M
V1= initial volume of the solution = 99.4 × 10^-3 L
C2 = concentration after dilution = 55 × 10^-3 M
V2 = volume after dilution = the unknown
V2 = C1 V1/C2
V2 = 152 × 10^-3 × 99.4 × 10^-3 / 55 × 10^-3
V2 = 0.275 L
The coefficients of the substances give you the ratio of the number of moles.
The 4 before the H2O and the 5 before the HCl tell you that for every 5 moles of HCl created, 4 moles of H2O had to react.
Therefore:

can be used to find the moles of H2O that react.
<span>Answer:
Correct answers are- Electron affinity decreases; Cl has 7 valence electrons but Na has only 1. So Na is going to lose its e, Cl is going to gain an e.</span>
Molarity is a unit of concentration defined as the number of moles of solute (the substance being dissolved) per volume of solution (the solvent in which all the solute is dissolved). Mathematically, molarity is expressed as
.
In this question, we are given the molarity and the volume of a solution of NaCl. We can use this information to calculate the number of moles of NaCl present in the solution. Rearranging the equation to solve for moles of solute, we multiply the molarity by the volume of the solution (the units for volume must be in liters, so 125 mL is expressed as the equivalent 0.125 L):

The question asks for the number of moles of NaCl in this solution, so number 3 would be correct.