Why must contact lenses be removed before you enter a chemistry laboratory?

1 answer:

6 0

The vapors of some chemicals used in the chemistry laboratory, especially isocyanates, can react and bond the contact lens to the eye.

(FYI - the family of isocyanates include Superglue..I wouldn't want to have been the person who discovered this unfortunate reaction!)

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decomposition of hydrogen peroxide produce water and oxygen . calculate the volume of O2 formed from the decomposition of 150 mL

Ugo [173]

Explanation:

2H2O2 => 2H2O + O2

Moles of hydrogen peroxide = 0.150dm³ * (0.02mol/dm³) = 0.003mol .

Moles of oxygen = 0.0015mol.

Volume of oxygen = 0.0015mol * (22.4dm³/mol) = 0.0336dm³.

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2 years ago

How does a filter separate mixtures like sand and water?

Talja [164]

Answer:

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Explanation:

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2 years ago

When 74.8g of alanine C3H7NO2 are dissolved in 1450.g of a certain mystery liquid X, the freezing point of the solution is 8.30°

dlinn [17]

Answer: The mass of potassium bromide that must be dissolved in the same mass of X to produce the same depression in freezing point is 58.2 grams

Explanation:

Depression in freezing point is given by:

$\Delta T_f=i\times K_f\times m$

$\Delta T_f=T_f^0-T_f=8.30^0C$ = Depression in freezing point

i= vant hoff factor = 1 (for non electrolyte)

$K_f$ = freezing point constant =

m= molality = $\frac{\text{mass of solute}}{\text{molar mass of solute}\times \text{weight of solvent in kg}}=\frac{74.8g\times 1000}{1450g\times 89.09g/mol}=0.579$