Answer:
KBr
Explanation
KBr is an ionic compound which have very high BP since they exist as 3D crystals
Methyl Bromide, CH3Br. is a covalent compound which have low BP since they exist as individual molecules
Answer:
exothermic
Explanation:
This chemical reaction is an exothermic reaction because heat is liberated into the environment.
In organic chemistry, the reaction is termed a combustion reaction. In such a reaction, a fuel combines with oxygen to produce carbon dioxide and water.
It is an energy transformation from chemical energy to heat energy.
- An exothermic reaction is one in which heat is liberated to the surrounding.
- The surrounding becomes hotter at the end of the reaction.
In the reaction depicted, heat is liberated.
Answer:
C.
Explanation:
Scientific notation is a way of writing small and large numbers. It is a way of expressing a standard form into a scientific form.
Answer:

Explanation:
<u>1. Convert Molecules to Moles</u>
First, we must convert molecules to moles using Avogadro's Number: 6.022*10²³. This tells us the number of particles in 1 mole of a substance. In this case, the particles are molecules of sodium hydroxide.

Multiply by the given number of molecules.

Flip the fraction so the molecules cancel out.




<u>2. Convert Moles to Grams</u>
Next, we convert moles to grams using the molar mass.
We must calculate the molar mass using the values on the Periodic Table. Look up each individual element.
- Na: 22.9897693 g/mol
- O: 15.999 g/mol
- H: 1.008 g/mol
Since the formula has no subscripts, we can simply add the molar masses.
- NaOH: 22.9897693+15.999+1.008=39.9967693 g/mol
Use this as a ratio.

Multiply by the number of moles we calculated.

The moles of sodium hydroxide cancel.



The original measurement of molecules has 3 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place. The 0 tells us to leave the 7 in the hundredth place.

1.20*10²² molecules of sodium hydroxide is approximately 0.797 grams.
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