A substance with a definite volume and a definite shape is classified as a what?
1 answer:
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Answer:
- Question 19: the three are molecular compounds.
- Question 20: CuSO₄.5H₂O
Explanation:
<em>Question 19.</em>
- C₂H₄
- HF
- H₂O₂
All of them are the combination of two kinds of different atoms in fixed proportions.
- C₂H₄: two carbon atoms per four hydrogen atoms
- HF: one hydrogen atom per one fluorine atom
- H₂O₂: two hydrogen atoms per two oxygent atoms
Thus, they all meet the definition of compund: a pure substance formed by two or more different elements with a definite composition.
Molecular compounds are formed by covalent bonds and ionic compounds are formed by ionic bonds.
Two non-metal elements, like H-F, C - C, C - H, H-O, H - H, and O - O will share electrons forming covalent bonds to complete their valence shell. Thus, the three compounds are molecular and not ionic.
<em>Question 20. </em>Formula of copper(II) sulfate hydrate with 36.0% water.
Copper(II) sulfate is CuSO₄. Its molar mass is 159.609g/mol
Water is H₂O. Its molar mass is 18.015g/mol
Calling x the number of water molecules in the hydrate, the percentage of water is:
From which we can solve for x:
Thus, there are 5 molecules of water per each unit of CuSO₄, and the formula is:
- CuSO₄.5H₂O
Answer:
Approximately 1.9 kilograms of this rock.
Explanation:
Relative atomic mass data from a modern periodic table:
- Pb: 207.2;
- S: 32.06.
To answer this question, start by finding the mass of Pb in each kilogram of this rock.
89% of the rock is . There will be 890 grams of
in one kilogram of this rock.
Formula mass of :
.
How many moles of formula units in that 890 grams of
?
.
There's one mole of in each mole of
. There are thus
of
in one kilogram of this rock.
What will be the mass of that of
?
.
In other words, the in 1 kilogram of this rock contains
of lead
.
How many kilograms of the rock will contain enough to provide 1.5 kilogram of
?
.