1. 254 cal = 1,062.736 joules
2. 126 cal = 527.184 joules
3. 98 cal = 410.032 joules
4. 704 cal = 2,945.536 joules
5. 682 cal = 2,853.488 joules
Answer: e) all of these
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: water
, carbon dioxide 
Mixtures are not pure substances as they consist of elements and compounds combined physically and not in any fixed ratio. Example: Air
Thus all given substances are pure substances.
Answer:
i promise you it's b
Explanation:
its not a or d because gasses are on the right side, its not d because metals are not brittle, and it's not c because theyre good conducters not insulators
Answer:-
190.23 gram mol-1
Explanation:-
Molar mass is the mass of 1 mole of that substance. It's unit is gram / mol or gram mol-1.
For an element it is equal to it's atomic weight.
The atomic weight of Osmium is 190.23
Hence the molar mass of Osmium is 190.23 gram / mol
Answer:
Hydrogen bond is formed only by the three highly electronegative elements- fluorine, oxygen and nitrogen.