Answer:
1 x 10^-12 mol dm^-3
Explanation:
[H+] = 10 ^ -pH
Therefore, pH 12 = 1 x 10^-12 hydrogen ion concentration
Answer:
Percentage yield = 85.2%
Explanation:
Given data:
Mass of Mg = 21.3 g
Actual yield of MgO = 30.2 g
Percentage yield = ?
Solution:
Chemical equation:
2Mg + O₂ → 2MgO
Number of moles of Mg = mass/molar mass
Number of moles of Mg = 21.3 g / 24.3 g/mol
Number of moles of Mg = 0.88 mol
Now we will compare the moles of MgO with Mg.
Mg : MgO
2 : 2
0.88 : 0.88
Mass of MgO:
Mass of MgO= moles × molar mass
Mass of MgO= 0.88 mol × 40.3g/mol
Mass of MgO = 35.46 g
Actual yield of MgO = 30.2 g
Percentage yield:
Percentage yield = Actual yield/theoretical yield × 100
Percentage yield = 30.2 g/ 35.46 g × 100
Percentage yield = 85.2%
Answer:
8700
Explanation:
First, do the operations i<em>nside parentheses</em>.
102 900/12 = 8600 2 sfs because of 12
170/1.27 = 130 2 sfs because of trailing 0 in 170
===============
Now, do the addition.
8600
<u> + </u><u>13</u><u>0
</u>
8700
The answer has two significant figures because when adding, you must round your answer to the same "place" as the measurement with its last significant figure furthest to the left.
The last significant figure in 8600 (the 6, in the hundreds place) is further to the left than the last significant figure in 130 (the 3, in the tens place).
We round off to the nearest hundred and get the answer, 8700.
Answer:
The main purpose of the expedition was to conduct a hydrographic survey of the coasts of the southern part of South America.
