The molarity of the stock solution is 1.25 M.
<u>Explanation:</u>
We have to find the molarity of the stock solution using the law of volumetric analysis as,
V1M1 = V2M2
V1 = 150 ml
M1 = 0.5 M
V2 = 60 ml
M2 = ?
The above equation can be rearranged to get M2 as,
M2 = 
Plugin the values as,
M2 = 
= 1.25 M
So the molarity of the stock solution is 1.25 M.
Answer : The amount of formaldehyde permissible are, 
Explanation : Given,
Density of air =

First we have to calculate the mass of air.



Now we have to calculate the amount of formaldehyde.
Permissible exposure level of formaldehyde = 0.75 ppm = 
Amount of formaldehyde in 7.2 g of formaldehyde = 
Amount of formaldehyde in 7.2 g of formaldehyde = 
Thus, the amount of formaldehyde permissible are, 
Physical
When something is cooling it isn’t changing it’s chemical composition so it’s physical
Answer:
3.54 mol
Explanation:
Step 1: Given data
- Temperature (T): 45.00 °C
Step 2: Convert "T" to Kelvin
We will use the following expression.
K = °C + 273.15
K = 45.00°C + 273.15 = 318.15 K
Step 3: Calculate the number of moles (n) of argon gas
We will use the ideal gas equation.
P × V = n × R × T
n = P × V/R × T
n = 2.50 atm × 37.0 L/(0.0821 atm.L/mol.K) × 318.15 K = 3.54 mol