Answer: 2. cannot be an element.
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Copper 
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: methane 
Thus as it can be decomposed into its constituent elements, it is a compound.
Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present.
Thus methane cannot be an element.
Explanation:
Calcium chloride is an ionic compound as it is formed by transfer of an electron to each chlorine atom.
So, being an ionic compound calcium chloride is able to dissociate completely into water.
Hence, the dissociation reaction will be as follows.
Since, two electrons has been lost by single calcium atom. Therefore, calcium atom will have a charge of +2.
Thus, we can conclude that the charge on the calcium ion, in elementary units is +2.
Answer:
C. Cs < K < P
Explanation:
Electronegativity is the basically the tendency of an atom to attract electrons. The pauling scale is used to quantify electronegativity, the most electronegative element; fluorine has a value of 4.0 and francium, the least electronegative element has a value of 0.7
The electronegative values of the following elements are given as;
K = 0.82
Cs =0.79
P = 2.19
Arranging in order of increasing electronegativity, we have;
Cs < K < P. The correct option is;
C. Cs < K < P
Answer:
Explanation:
2S + 3O₂ = 2SO₃
2moles 3 moles
2 moles of S react with 3 moles of O₂
5 moles of S will react with 3 x 5 / 2 moles of O₂
= 7.5 moles of O₂ .
O₂ remaining unreacted = 10 - 7.5 = 2.5 moles .
All the moles of S will exhausted in the reaction and 2.5 moles of oxygen will be left .
What's the big M? Molecular weight or mol?
