An atomic mass unit is defined as precisely 1/12 the mass of an atom of carbon-12.
Answer:
The mass of water
= 39.18 gm
Explanation:
Mass of iron
= 32.5 gm
Initial temperature of iron
= 22.4°c = 295.4 K
Specific heat of iron
= 0.448 
Mass of water =
Specific heat of water 
Initial temperature of water
= 336 K
Final temperature after equilibrium
= 59.7°c = 332.7 K
When iron rod is submerged into water then
Heat lost by water = Heat gain by iron rod
(
-
) =
(
-
)
Put all the values in above formula we get
× 4.2 × ( 336 - 332.7 ) = 32.5 × 0.448 × ( 332.7 - 295.4 )
= 39.18 gm
Therefore the mass of water
= 39.18 gm
<u>Answer:</u> The molality of
solution is 0.782 m
<u>Explanation:</u>
Molality is defined as the amount of solute expressed in the number of moles present per kilogram of solvent. The units of molarity are mol/kg. The formula used to calculate molality:
.....(1)
Given values:
Moles of
= 0.395 mol
Mass of solvent (water) = 0.505 kg
Putting values in equation 1, we get:

Hence, the molality of
solution is 0.782 m
Answer:
1.1 × 10²⁴ atoms Mg
General Formulas and Concepts:
<u>Atomic Structure</u>
- Moles
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
<u>Stoichiometry</u>
- Using Dimensional Analysis
Explanation:
<u>Step 1: Define</u>
<em>Identify</em>
[Given] 1.8 mol Mg
[Solve] atoms Mg
<u>Step 2: Identify Conversions</u>
Avogadro's Number
<u>Step 3: Convert</u>
- [DA] Set up:

- [DA] Multiply [Cancel out units]:

<u>Step 4: Check</u>
<em>Follow sig fig rules and round. We are given 2 sig figs.</em>
1.08396 × 10²⁴ atoms Mg ≈ 1.1 × 10²⁴ atoms Mg