This technique can be used to make pure crystals of a soluble salt.
The burette is filled with hydrochloric acid.
A known quantity of alkali (say 50 cm3 sodium hydroxide)
is released from a pipette into the conical flask.
The tap on the burette is turned open to allow
the acid to be added drop by drop into the alkali.
The alkali contains an indicator (phenolphthalein)
which is pink in an alkali and colorless in an <span>acid.
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When enough acid has been added to neutralize
the alkali, the indicator changes from
pink to colorless. This is the end point of the titration.
The titration<span> can be repeated using the </span><span>same amounts
</span><span>of </span>acid<span> and </span>alkali<span> but </span>without<span> the </span>indicator.
<span>Pure salt</span> crystals<span> which are </span>free<span> from </span><span>indicator
</span><span>can then be crystallized </span><span> from the </span>neutral<span> solution.</span>
First convert the 2 temperatures to degrees K:
4 + 273 ---> 277 and 22---> 295
So using Charles' Law
V1 / T1 = V2 / T2
0.50 / 295 = V2 / 277
solving for V2 gives a volume of 0.469 L to nearest milliliter
Answer:
Oxygen is the limiting reactant.
Explanation:
Based on the reaction:
C₁₂H₂₂O₁₁ + 12O₂ → 12CO₂ + 11H₂O
<em>1 mole of sucrose reacts with 12 moles of oxygen to produce 12 moles of CO₂ and 11 moles of H₂O.</em>
<em />
10.0g of sucrose (Molar mass: 342.3g /mol) are:
10.0g C₁₂H₂₂O₁₁ × (1mole / 342.3g) = 0.0292 moles of C₁₂H₂₂O₁₁
And moles of 10.0g of oxygen (Molar mass: 32g/mol) are:
10.0g O₂ × (1mole / 32g) = 0.3125 moles of O₂
For a complete reaction of 0.0292 moles of C₁₂H₂₂O₁₁ you need (knowing 12 moles of oxygen react per mole of sucrose):
0.0292 moles of C₁₂H₂₂O₁₁ × (12 moles O₂ / 1 mole C₁₂H₂₂O₁₁) = <em>0.3504 moles of O₂</em>
As you have just 0.3125 moles of O₂, <em>oxygen is the limiting reactant.</em>
Answer:
b. mercury
Explanation:
Fishes and some other sea foods are are known to concentrate mercury in their bodies. Consumption of these products gradually accumulate mercury in the body over time.
More specifically, fishes like swordfish, king mackerel and shark are known to concentrate higher amount of mercury than other species of fishes. Hence, limiting their consumption will protect humans from mercury poisoning.
The correct option is b.
Answer:
Water droplets form on plants, allowing the plants to soak up the water over time rather than all at once.
Explanation:
Cohesion and Adhesion are the properties of water which affect the living and non-living on earth.
Cohesion means water is attracted to water.
Adhesion means water is attracted to other living beings.
Water is very cohesive in that it "sticks" to itself. Cohesion is what allows a water droplet to form, for example. When water molecules surround one another, they settle toward a low energy state. For water molecules, they are most stable when they form a ball surrounded by other water molecules. As the molecules "pull" together, the surface tension acts like a casing for the group of water molecules. If it weren't for cohesion, water molecules would behave very differently and we would not expect to see water droplets.
Cohesive and adhesive properties of water impact living things in many ways:
Water droplets form on plants, allowing the plants to soak up the water over time rather than all at once.
Water striders (insects) glide across water surfaces owing to the cohesive property of water.
