Answer:
10.60 grams of silane gas are formed.
Explanation:
From the reaction:
Mg₂Si(s) + 4H₂O(l) → 2Mg(OH)₂(aq) + SiH₄(g)
We know that the limiting reactant is Mg₂Si, so to find the mass of SiH₄ formed we need to calculate the number of moles of Mg₂Si:
Where:
m: is the mass of Mg₂Si = 25.0 g
M: is the molar mass of Mg₂Si = 76.69 g/mol
Now, the stoichiometric relation between Mg₂Si and SiH₄ is 1:1 so:
Finally, the mass of SiH₄ is:
Therefore, 10.60 grams of silane gas are formed.
I hope it helps you!
Answer:
3.65 g / ml correct to 3 sig. fig.
Explanation:
The computation of the concentration required is shown below:
As we know that
[A] = mass of solute ÷ volume of solution
Before that first find the mass of solute
Given that
Initial weight = 5.55g
And,
Final weight = 92.7 g
So,
Mass of KCl is
= 92.7 - 5.55
= 87.15 g ~ 87.2 g
Now the KCi is fully dissolved, so the volume is 23.9 ml
So, concentration is
= 87.2 g ÷ 23.9 ml
= 3.65 g / ml correct to 3 sig. fig.
Answer: It showed that all atoms contain electrons.
Explanation:
- J.J. Thomson's experiments inside a cathode ray tube in the presence of an electric field showed that all atoms contain tiny negatively charged subatomic particles "electrons".
- Also, Thomson's plum pudding model of the atom had negatively-charged electrons embedded within a positively-charged "soup."
- Furthermore, Rutherford's gold foil experiment showed that the atom is mostly empty space with a tiny positively-charged nucleus.
- Then, Rutherford proposed the nuclear model of the atom based on these results.
D. powder residues.
the police and forensic chemists usually perform a qualitative test called GPR or gun powder residue. the residue sticks to the skin.
