Unit A Science Questions (no definitions)

Question 1

what’s the difference between an ionic compound and a molecular compound?

Answer 1

ionic compounds are pure substances formed from metals and non-metals
that involves the attraction between positive and negative ions
whereas molecular compounds are formed exclusively from non-metals and do not involve ions.

Question 2

gaining electrons = what charge?

Answer 2

negative charge

Question 3

losing electrons = what charge?

Answer 3

positive charge

Question 4

on paper, solve how many moles of O2 molecules will be needed to react completely with 0.50 mol of NH3

4NH3 + 3O2 —> 2N2 + 6H2O

let x represent the number of moles of O2

Answer 4

ratio: 0.50/4 = x/3

conversion factor

0.50mol NH3 x 3mol O2 / 4mol NH3 = 0.38mol O2

always remember to first check if the equation is balanced before calculating the moles

Question 5

what does ethyl look like in a complete structural diagram?

Answer 5

CH3CH2

Question 6

what does methyl look like in a complete structural diagram?

Answer 6

CH3

Question 7

when aluminum metal is exposed to air, the metal reacts with oxygen in the air to form aluminum oxide

4 Al(s) + 3 O2(g) —-> 2 Al2O3(s)

a. if you react 6.25 mol of aluminum with a sufficient amount of oxygen, determine how many moles of aluminum oxide will be formed

b. determine the number of moles of oxygen required to react with 6.25 mol of aluminum

Answer 7

a.)

n(Al) = 6.25 mol

n(Al2O3) = ?

n(Al2O3) / n(Al) = coefficient (Al2O3) / coefficient (Al)

n(Al2O3) / n(Al) = 2/4

n(Al2O3) = 2/4 x n(Al)

= 2/4 x 6.25 mol

= 3.13 mol

b.)

same process as (a) substitute correct values in the formula

Question 8

most acids (like HCl) are in what phase

(g) (s) (l) (aq)?

Answer 8

aqueous, as they mostly dissolve in water

Question 9

which bonds are more reactive? triple bonds (alkynes) or single bonds (alkanes)

Answer 9

single bonds, or alkanes are the least reactive while triple bonds (alkynes) are the most reactive