Answer:
<em>- 0.0413°C ≅ - 0.041°C (nearest thousands).</em>
Explanation:
- Adding solute to water causes the depression of the freezing point.
<em>ΔTf = Kf.m,</em>
Where,
ΔTf is the change in the freezing point.
Kf is the freezing point depression constant (Kf = 1.86 °C/m).
m is the molality of the solution.
<em>Molality is the no. of moles of solute per kg of the solution.</em>
- <em>no. of moles of solute (glucose) = mass/molar mass</em> = (8.44 g)/(180.156 g/mol) = <em>0.04685 mol.</em>
<em>∴ molality (m) = no. of moles of solute/kg of solvent</em> = (0.04685 mol)/(2.11 kg) = <em>0.0222 m.</em>
∴ ΔTf = Kf.m = (1.86 °C/m)(0.0222 m) = 0.0413°C.
<em>∴ The freezing point of the solution = the freezing point of water - ΔTf </em>= 0.0°C - 0.0413°C = <em>- 0.0413°C ≅ - 0.041°C (nearest thousands).</em>
Answer:
Moving Across a Period
Moving from left to right across a period, the atomic radius decreases. The nucleus of the atom gains protons moving from left to right, increasing the positive charge of the nucleus and increasing the attractive force of the nucleus upon the electrons
A metalloid is a type of chemical element which has a preponderance of properties in between, or that are a mixture of, those of metals and nonmetals.
Dmitri Mendeleev, he realized that the physical and chemical properties of elements were related to their atomic mass and arranged them into groups (columns)
Answer:
a. 211.7
Explanation:
Iron Pyrite reacts with Oxygen to produce Iron (II) Oxide and Sulphur (IV) Oxide.
The equation is as follows:
4FeS₂₍s₎ + 11O₂₍g₎ → 2Fe₂O₃₍s₎ + 8SO₂₍g₎
From the equation, 4 moles of FeS₂ produce 8 moles of SO₂.
Therefore the reaction ratio is 4:8 or 1:2
198.20 grams of FeS₂ into moles is calculated as follows:
Moles= Mass/RMM
RMM of FeS₂ is 119.9750g/mol.
Number of moles = 198.20/119.9750g/mol
=1.652 moles of FeS₂
The reaction ratio of FeS₂ to SO₂ produced is 1:2
Thus SO₂ produced = 1.652 moles×2/1=3.304 moles
The mass of SO₂ produced =Moles ×RMM
=3.304 moles ×64.0638 g/mol
=211.667 grams
=211.7g
