Answer:
Explanation:
When we react Hydrochlorid Acid with zinc we have the following reaction:
2HCl(aq) + Zn(s) --> ZnCl2(aq) + H2(g)
The hydrogen gas formed is lost to the environment, so we can affirme that in the start we have the mass for all the H, Cl and Zn atoms in the solution, but after the reaction occurs, we have only the mass for the Cl and Zn atoms.
That's why the mass is less than the original.
The law that the student was told is only applied to closed environments.
250cm3 i think im not sure about it though
As we know that
<span>V1/T1 = V2/T2
V1 = 9.10 L
T1 = 471 K
V2 = 2.50 L
T2 = 2.5 x 471 / 9.10 = 129.3 K
T2 = 129.3 - 273 =
-143.6 deg Celsiu
hope it helps</span>
Answer:

Explanation:
Group 4A contains a total of 4 electrons for each atom in their valence shell. Filling the orbital diagram, let's say, for carbon, notice that when we start with period 2, we have two elements in the s-block, that is, lithium and beryllium. They correspond to the two s electrons that belong to the valence shell of carbon.
Moving on, we have boron and carbon, the remaining 2 electrons. Now, starting with boron, we're in the p-block.
That said, looking at the second period, the electron configuration for the valence shell of a group 4A element would be:
