Sorry if I'm wrong but it's 1) learner engages in scientifically oriented questions. 2) learner gives priority to evidence in responding to questions. 3) learners formulate explanations from evidence. 4) learner connects explanations to scientific knowledge. 5) learner communicates explanations.
I think the answer is D. the upper surface of undergound water.
Answer:
8.1107 g
Explanation:
The given reaction:

Given that:
Mass of silver sulfadiazine = 25.0 g
Molar mass of silver sulfadiazine = 357.14 g/mol
The formula for the calculation of moles is shown below:
Thus,

From the reaction,
2 moles of silver sulfadiazine are formed from 1 mole of silver oxide
So,
1 mole of silver sulfadiazine are formed from 1/2 mole of silver oxide
0.07 mole of silver sulfadiazine are formed from 1/2*0.07 mole of silver oxide
Moles of silver oxide = 0.035 moles
Molar mass of silver oxide = 231.735 g/mol
Mass = Moles * Molar mass = 0.035 moles * 231.735 g/mol = 8.1107 g
Answer is: 4.0 mol of lithium nitride would be produced.
Balanced chemical reaction: 6Li + N₂ → 2Li₃N.
n(Li) = 12 mol; amount of substance.
From chemical reaction: n(Li) : n(Li₃N) = 6 : 2 (3 : 1).
n(Li₃N) = n(Li) ÷ 3.
n(Li₃N) = 12 mol ÷ 3.
n(Li₃N) = 4 mol; amount of lithium nitride.
Answer:
Na₂CO₃ · 10H₂O
Explanation:
The formula for sodium carbonate hydrate is:
Na₂CO₃ · xH₂O
The unknown "x" is the number of water molecules contained in the hydrate.
To find "x" we have to use the hydrogen percentage in the sample, 7.05 % H.
First we calculate the molecular weight of Na₂CO₃ · xH₂O:
molecular weight of Na₂CO₃ · xH₂O = 23 × 2 + 12 + 16 × 3 + 18x
molecular weight of Na₂CO₃ · xH₂O = 106 + 18x g/mole
Now we devise the fallowing reasoning tanking in account 1 mole of Na₂CO₃ · xH₂O:
if in 106 + 18x grams of Na₂CO₃ · xH₂O we have 2x grams of hydrogen
then in 100 grams of Na₂CO₃ · xH₂O we have 7.05 grams of hydrogen
106 + 18x = (100 × 2x) / 7.05
106 + 18x = 28.4x
106 = 28.4x - 18x
106 = 10.4x
x = 106 / 10.4
x = 10.2 ≈ 10
The formula for the washing soda is Na₂CO₃ · 10H₂O.