Answer:
Physical
Explanation:
The change of density alone is a physical change, but there might be some chemical change that results in physical change. For example: Burning a piece of paper will definitely change the density of the paper as some of its content is being changed into smoke which is a gas. So there will be a change in volume which in turn leads to change in density. Therefore, the change of density alone is a physical change, but the change might occur due to another chemical change.
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Answer:
The answer to your question is below
Explanation:
Trial 1 Trial 2
mass of Mg 0.255 g 0.353 g
mass of MgO 0.418 g 0.576 g
Chemical reaction
2Mg(s) + O₂(g) ⇒ 2MgO(s)
Question 1.
Atomic mass of Mg = 24.31 x 2 = 48.62 g
Molecular mass of MgO = 2(24.31 + 16) = 80.62 g
Trial 1
48.62 g of Mg ----------------- 80.62 g of MgO
0.255 g ---------------- x
x = (0.255 x 80.62)/48.62
x = 0.422 g of MgO
Trial 2 48.62 g of Mg ----------------- 80.62 g of MgO
0.353 g ---------------- x
x = (0.353 x 80.62)/48.62
x = 0.585 g of MgO
Question 2
Trial 1
Percent yield = 0.418/0.422 x 100 = 99%
Trial 2
Percent yield = 0.576/0.585 x 100 = 98.5%
Question 3
Average = (99 + 98.5)/2
= 98.75%
Cesium is the biggest, atom wise.It has 55 protons.
Answer: When a substance is pure, it is composed of one type of molecule. For example, table salt is only composed of (more or less) salt molecules, while seawater has water and salt molecules. A more complicated example of a non - pure substance is soil. It has many different types of nutrients and compounds.
Well one mole of stuff, any stuff, including carbon dioxide, specifies
6.022
×
10
23
individual items of that stuff.
Explanation:
And thus we work out the quotient:
7.2
×
10
25
⋅
carbon dioxide molecules
6.022
×
10
23
⋅
carbon dioxide molecules
⋅
m
o
l
−
1
≅
120
⋅
m
o
l
carbon dioxide
.
This is dimensionally consistent, because we get an answer with units
1
m
o
l
−
1
=
1
1
mol
=
m
o
l
as required.
