Answer:
c
Explanation:
there will be displacement reaction taking place
The molarity of a solution is a type of expression of concentration equal to the number of moles solute per liter solution. In this problem, we are given the molarity equal to 0.75 M and a volume equal to 500 milliliters. <span>500 milliliters is equal to 0.5 liters. we multiply M and L to get the number of moles then multiply by the molar mass of NaCl. The answer is 21.92 grams.</span>
Answer:
3.5 moles Fe
Explanation:
From the equation, Reaction of 2 moles of Fe₂O₃ with 1 mole of C produces 1 mole of Fe. When excess Fe₂O₃ is used, the only liming factor is C.
The ratio of amount of C used to the amount of Fe produced is 1:1
Therefore, if 3.5 moles of C are used, 3.5 moles of Fe are also produced.
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, 