A liquid solution of formaldehyde is 37.0% pure. This solution has a specific gravity of 1.037. The molecular weight of formaldehyde is 30.0. to 1.00 ml of this impure stock solution is added quantity sufficient to take the total volume to 500ml. If 1.00 ml of this solution is added to 4ml of water in a final reaction, what is the molarity of formaldehyde in this final reaction tube?
one tryoy ounce of gold is worth 380.00. There are 33.8 grams per troy ounce. you have a stock colloidal solution of a ver fine gold dust. It's concentration is .10%. From this solution 1.0ml is placed in 9.0ml of an isotonic, pH buffered solution to make a working stock. An assay call for .50 ml of this working stock to which is added .10 ml of serum. What is the cost of gold used for each test?
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To find the molarity of formaldehyde in the final reaction tube, we need to calculate the amount of formaldehyde present in the 1.00 ml of the impure stock solution and then consider its dilution when mixed with water.
First, let's calculate the amount of formaldehyde in the 1.00 ml of the impure stock solution:
Amount of formaldehyde = volume of stock solution (1.00 ml) × concentration of formaldehyde in stock solution (37.0% or 0.37)
Amount of formaldehyde = 1.00 ml × 0.37 = 0.37 ml
Since the density of the stock solution is not given, we cannot directly convert ml to grams. However, we can use the specific gravity of the solution to estimate the mass of the stock solution.
Mass of stock solution = volume of stock solution (1.00 ml) × specific gravity (1.037)
Mass of stock solution = 1.00 ml × 1.037 = 1.037 g
Now, we need to calculate the molarity of the stock solution:
Molarity = amount of solute (in moles) / volume of solution (in liters)
To convert the mass of formaldehyde to moles, we need to divide it by the molecular weight of formaldehyde:
Moles of formaldehyde = mass of formaldehyde / molecular weight of formaldehyde
Moles of formaldehyde = 1.037 g / 30.0 g/mol = 0.0346 mol
Since the total volume of the final reaction is 5.00 ml (1.00 ml of stock solution + 4.00 ml of water), we can now calculate the molarity of formaldehyde in the final reaction tube:
Molarity = moles of formaldehyde / volume of solution (in liters)
Molarity = 0.0346 mol / 0.00500 L = 6.92 M
Therefore, the molarity of formaldehyde in the final reaction tube is 6.92 M.