Answer:
<u>The Answer is (B) A car get rusty over the course of few years</u>Explanation:
<u>Explanation:</u>
- <u>Oxidation </u>refers to the process of loss of electrons by a molecule,atom or ion during a chemical reaction.The process which is just the opposite of oxidation is reduction,it occurs when their is gain of electrons .
- <u>When iron reacts with the oxygen it forms a chemical know as Rust.In this case iron has lost some electrons and the oxygen has gained some electrons</u>
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Explanation:
A cup of mixtures of iron fillings, sand and salt is a mixture who constituents are in the same phase i.e solid.
To separate them out we use the physical properties of the substances.
- First spread out the mixture uniformly over a piece of paper or on the table.
- Pass a bar magnet over it.
- The iron fillings will become attracted to the magnet and separate from the mixture.
- then pour water into the mixture of sand and salt
- the salt will dissolve since sand is made up of quartz which are highly insoluble.
- separate the water solution. Evaporate to dryness and recover the salt.
- the sand is left behind and dried.
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Answer:

Explanation:
You must convert 30 % (m/v) to a molar concentration.
Assume 1 L of solution.
1. Mass of NaOH

2. Moles of NaOH

3. Molar concentration of NaOH

4. Volume of NaOH
Now that you know the concentration, you can use the dilution formula .

to calculate the volume of stock solution.
Data:
c₁ = 7.50 mol·L⁻¹; V₁ = ?
c₂ = 0.1 mol·L⁻¹; V₂ = 250 mL
Calculations:
(a) Convert millilitres to litres

(b) Calculate the volume of dilute solution


Answer:
130.4 grams of sucrose, would be needed to dissolve in 500 g of water.
Explanation:
Colligative property of boiling point elevation:
ΔT = Kb . m . i
In this case, i = 1 (sucrose is non electrolytic)
ΔT = Kb . m
0.39°C = 0.512°C/m . m
0.39°C /0.512 m/°C = m
0.762 m (molality means that this moles, are in 1kg of solvent)
If in 1kg of solvent, we have 0.712 moles of sucrose, in 500 g, which is the half, we should have, the hallf of moles, 0.381 moles
Molar mass sucrose = 342.30 g/m
Molar mass . moles = mass
342.30 g/m . 0.381 m = 130.4 g
<span>masss % of KBr = mass of KBr/total mass of solution X 100 = 50/100 X 100 = 50 %</span>