Answer:
Explanation:1.8
×
10
24
water molecules.
Explanation:
There are
6.022
×
10
23
molecules in a mole.
There are
18.01528
grams of water per mole of water.
These can be figured out using the concept of moles and molecular weight. I have attached a video that provides a good explanation.
Explanation of moles and molecular weight
Now you have all the information needed to solve the problem.
You start out with 54 grams of water. You want to convert that into molecules, but how can you do that? You can't go directly from grams to molecules because there is no easy unit conversion. However, you can go from grams to moles using
18.01528
grams of water per mole of water.
From there, you can go from moles to molecules using
6.022
×
10
23
molecules in a mole.
A T chart is useful for this kind of problem.
54 g H
2
O
×
1 mol H
2
O
18.0152 g H
2
O
×
6.022
×
10
23
molecules
1 mol H
2
O
54
g H
2
O
×
1 mol H
2
O
18.0152
g H
2
O
×
6.022
×
10
23
molecules
1 mol H
2
O
Notice when you apply this T chart, the units cancel out, leaving molecules in the final answer, which is the correct units.
Now actually multiply everything out
54
×
6.022
×
10
23
18.0152
=
1.805
×
10
24
You are left with
1.8
×
10
24
water molecules (rounded to two sig figs).
The correct answer is option 4, that is, an ionic compound.
The mentioned features belong to an ionic compound. The ionic compounds exhibit strong bonds in between their atoms, that is, an ionic bond is the strongest molecular bond, this confirms that ionic compounds exhibit a high melting point.
The ionic compounds do not transmit current, as they do not possess free electrons, like metals, thus, they are poor conductors as solid. The ionic compounds get dissolve in water and form ions that are the charges, which can move, making them good conductors as a liquid. The composition of the ionic compound is a set of crystals that makes them brittle and hard.
First determine the formal oxidation numbers:
N changes from +2 to +5 going from NO to (NO3)- O remains -2 the whole time Cr changes from +6 to +3
Now write the half reactions, balance the oxygens with the required number of waters and then balance the hydrogens with the required number of protons:
Oxidation half reaction:
NO(aq) + 2 H2O(l) ---> (NO3)-(aq) + 4 H+(aq) + 3 e-
Reduction half reaction:
(Cr2O7)2-(aq) + 14 H+(aq) + 6 e- ---> 2 Cr3+(aq) + 7 H2O(l)
Now balance the number of electrons on both sides and add them together:
2 NO(aq) + 4 H2O(l) ---> 2 (NO3)-(aq) + 8 H+(aq) + 6 e- (Cr2O7)2-(aq) + 14 H+(aq) + 6 e- ---> 2 Cr3+(aq) + 7 H2O(l) --------------------------------------... 2 NO(aq) + (Cr2O7)2-(aq) + 6 H+(aq) ---> 2 (NO3)-(aq) + 2 Cr3+(aq) + 3 H2O(l)
Notice that the charge is the same in both sides, which is an indication that the redox equation has been balanced correctly:
-2 + 6 = -2 + 2(+3) +4 = +4
Answer:
Image result for What materials are needed to find density of water
Calculate the density by dividing the mass by the volume.
Using the equation density = mass/volume, you can determine the density of water. Plug in the values of mass and volume you determined and solve.
Explanation:
