Answer:
- Question 19: the three are molecular compounds.
Explanation:
<em>Question 19.</em>
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:
Answer:
A particular atom will have the same number of protons and electrons and most atoms have at least as many neutrons as protons. An element is a substance that is made entirely from one type of atom
Explanation:
so In simple terms an atom contains Protons and Electrons and can be found in an Element, but an element comprises of atoms which come together to form up that particular Element
Answer:
Likely to gain electrons
Explanation:
The atom shown is likely to gain additional electrons to complete its electronic configuration.
- Since this is a neutral specie, the number of protons and electrons are the same.
- The atom has 16 electrons
- the number of valence electrons is 6
- If the atom gains two additional electrons, the octet configuration is attained
- Also, the atom can lose 6 electrons to become an octet
The atom will prefer to gain additional 2 electrons to give an octet configuration.
Answer:
2Fe + 3Cl2 → 2FeCl3
Explanation:
Fe + Cl2 —> FeCl3
There are 3atoms of Cl on the right side and 2 atoms on the left side. Therefore, to balance Cl put 2 in front of FeCl3 and put 3 in front of Cl2 as shown below:
Fe + 3Cl2 → 2FeCl3
Now, we see clearly that there are 2 atoms of Fe on the right side and 1 on the left side. This can be balanced by putting 2 in front of Fe as shown below:
2Fe + 3Cl2 → 2FeCl3
Now the equation is balanced.
Answer: 0.4 g
Explanation:
1) Balanced chemical equation:
2) 2C2H2 + 5 O2 → 4CO2 + 2 H2O
3) mole ratios:
2 mol C2h2 : 5 mol O2
4) Convert 0.13 g C2H2 into number of moles
n = mass in grams / molar mass
molar mass C2H2 = 2 *12g/mol + 2*1 g/mol = 26 g/mol
n = 0.13 g / 26 g/mol = 0.005 mol
5) Set the proportion with the unknown
5 mol O2 x
----------------- = ---------------
2 mol C2H2 0.005 mol C2H2
x = 0.005 mol C2H2 * 5 mol O2 / 2 mol C2H2 = 0.0125 mol O2
6) Convert 0.0125 mol O2 to grams
mass = number of moles * molar mass
molar mass of O2 = 32 g/mol
mass = 0.0125 mol * 32 g/mol = 0.4 g
Answer: 0.4 g
