Answer:
5.46 8 x 10²³ molecules.
Explanation:
- <em>Knowing that every one mole of a substance contains Avogadro's no. of molecules (NA = 6.022 x 10²³).</em>
<em><u>Using cross multiplication:</u></em>
1.0 mole → 6.022 x 10²³ molecules.
9.08 x 10⁻¹ mole → ??? molecules.
∴ The no. of molecules of CO₂ are in 9.08 x 10⁻¹ mol = (6.022 x 10²³ molecules) ( 9.08 x 10⁻¹ mole) / (1.0 mol) = 5.46 8 x 10²³ molecules.
To find this, we will use this formula:
Molar mass of element
------------------------------------ x 100
Molar mass of compound
So, first lets calculate the mass of the compound as a whole. We use the atomic masses on the periodic table to determine this.
Ca: 40.078 g/mol
N2 (there is two nitrogens): 28.014 g/mol
O6 (there are six nitrogens: 3 times 2): 95.994 g/mol
When we add all of those numbers up together, we get 164.086. That is the molar mass for the whole compound. However, we are trying to figure out what percent of the compound oxygen makes up. From the molar mass, we know that 95.994 of the 164.086 is oxygen. Lets plug those numbers into our equation!
95.994
-----------
164.086
When we divide those two numbers, we get .585. When we multiply that by 100, we get 58.5.
So, the percent compostition of oxygen in Ca(NO3)2, or, calcium nitrate, is 58.5%.
I got 134.91 but if you round it you’ll get 135
1.) Gas given off
2.) precipitate formed
3.) large amount of heat given off
4.) Color change
Answer:
The volume of the piece of iron is 5.18dL.
Explanation:
The density (ρ) is equal to the mass (m) divided the volume (V).
If we rearrange it, we have:
To express the volume in dL we will need the following relations:
- 1 dL = 0.1 L
- 1 kg = 10³ g
- 1 cm³ = 1 mL
- 1mL = 10⁻³L
Then,
Finally,
