I believe the change of state shown in the model is deposition.
Deposition is a process in which gases change phase and turns directly in solids without passing through the liquid phase. It is the opposite of sublimation.
One of the major difference between gases and solids is the distance between molecules; in gases the inter molecular spaces are large, while in solid they are very small, making solids be the most dense, with closely packed molecules. This is evident in the diagram, the phase changed from gases to solids.
He answer is 42 because you carry the one
The reaction between calcium carbonate and hydrochloric acid can be expressed through the chemical reaction,
CaCO3 + 2HCl --> CaCl2 + H2O + CO2
The molecular weight of calcium carbonate is 100 g/mol while that of hydrochloric acid is 36.45. The equation above depicts that 100 g of calcium carbonate can be dissolved in 72.9 g of hydrochloric acid.
x = (4 g HCl)(100 g CaCO3 / 72.9 HCl)
x = 5.49 g
Answer: 5.49 g
