Answer:
The number of molecules in a mole (known as Avogadro's constant) is defined such that the mass of one mole of a substance, expressed in grams, is equal to the mean molecular mass of the substance. The molecular mass of CO2 = 12+2x16 = 44, so the mass of a mole of CO2 is approximalty 44 grams
Explanation:
1) Carbon dioxide is a gas, so when
is evolved in the reaction, it appears as bubbles. The gas released extinguishes the fire and it can turn lime water milky.

2) When
is released in a decomposition reaction we can identify by the strong pungent smell of the gas released.
3) Saturated citric acid can cause corrosion of the metal layers present in the pipes. So, before draining out any acid it is neutralized so that the pipes and other plumbing works do not get damaged leading to leaks in the drainage system.
Answer:
D:2
Explanation:
H is hydrogen, and the subscript represents the amount of atoms it has so H2SO is two hydrogens
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, 
Hydrogen sulfide = hidrogen + sulfur
6.500 g
a) 0.384 g + x
=> 6.500 = 0.384 + x => x = 6.500 - 0.384 = 6.116 g
Answer: 6.116 g of sulfur must be obtained
b) this experiment demonstrate the conservation of mass.
c) Dalton's atomic model states that the atoms cannot be created, split or be destroyed, and so in a chemical reaction the atoms rearrange but the number of each type of atoms remain constant, so the mass of each type of atoms and the total mass remain constant.