Friction of the air, and the surface it is on
C because the sodium (cation) bonds with the sulphate (anion) and then chloride (anion) and hydrogen (acting as a cation) bond together
Subtracting the mass of (flask+water) from the empty flask gives:
95.023 g - 85.135 g = 9.888 grams of water
Dividing this by the given volume of 10.00 mL water gives:
9.888 grams of water / 10.00 mL of water = 0.9888 g/mL of water
Therefore, based on this sample, the density of water is 0.9888 g/mL, which is close to the usually accepted approximation of 1 g/mL.
Answer:
The mass of the products left in the test tube will be less than that of the original reactants.
Explanation
The equation for the reaction is
Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)
1.0 3.0 3.9 0.1
Assume you started with 1.0 g of Mg.
It will react with 3.0 g of HCl to form 3.9 g of MgCl2 and 0.1 g of H2
.
Mass of reactants = mass of products
1.0 g + 3.0 g = 3.9 g + 0.1 g
4.0 g = 4.0 g
The Law of Conservation of Mass is obeyed.
However, your test tube and its contents will weigh 0.1 g less than it did before the reaction.
Does that contradict the Law of Conservation of Mass? It does not.
One of the products was the gas, hydrogen, and it escaped from the test tube. You weren't measuring all the products, so test tube and its contents weighed less than before.
