Answer:
The percentage (by mass) of KBr in the original mixture was 33.1%.
Explanation:
The mixture of KCl and KBr has a mass of 3.595g, thus the sum of the moles of KCl (<em>x</em>) multiplied by it molar mass (74.5g/mol) and the moles of KBr (<em>y</em>) multiplied by it molar mass (119g/mol) is the total mass of the mixture:
Also, after the conversion of KBr into KCl, the total mass of 3.129 g is only from KCl moles, hence
But the 0.042 moles came from the originals KCl and KBr moles, thus
Now it is possible to propose a system of equations:
Solving the system of equations,
0.010 moles of KBr multiplied it molar mass is
Therefore, the percentage (by mass) of KBr in the original mixture was:
%
Answer:Silicon is neither metal nor non-metal; it's a metalloid, an element that falls somewhere between the two. The category of metalloid is something of a gray area, with no firm definition of what fits the bill, but metalloids generally have properties of both metals and non-metals.
Explanation:
Answer:
The answer is D. 0.60 L
Explanation:
The balanced reaction equation including states of matter is;
H₂SO₄(aq) + 2NaOH(aq) → Na₂SO₄(aq) + 2H₂O(l)
More simple:
H2SO4 + 2NaOH → Na2SO4 + 2H2O
Now, we can see from this reaction equation that the mole ratio of NaOH to H2SO4 is 2:1
Number of moles of H2SO4 reacted = 1.2 moles
Hence;
2 moles of NaOH reacts with 1 mole of H2SO4
x moles of NaOH reacts with 1.2 moles of H2SO4
x = 2 * 1.2/1 = 2.4 moles of NaOH
Recall that;
Number of moles = Concentration * Volume
Volume = number of moles/concentration
Volume of NaOH is obtained from;
Volume = 2.4 moles/ 4.0 M
Volume = 0.60 L
Answer
Ozone occurs both in the Earth's upper atmosphere and at ground level. Ozone can be good or bad, depending on where it is found. Called stratospheric ozone, good ozone occurs naturally in the upper atmosphere, where it forms a protective layer that shields us from the sun's harmful ultraviolet rays. On the other hand, tropospheric ozone artificialy occurs in the lower atmosphere, where it polluts the air and slowly warms the earth.
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