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kap26 [50]
3 years ago
5

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

Chemistry
1 answer:
RUDIKE [14]3 years ago
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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What is the percent of nitrogen in dinitrogen pentoxide?
Lostsunrise [7]

Answer: D.) 25.9%

Explanation:

Dinitrogen pentoxide chemical formular : N2O5

Calculating the molar mass of N2O5

Atomic mass of nitrogen(N) = 14

Atomic mass of oxygen(O) = 16

Therefore molar mass :

N2O5 = (2 × 14) + (5 × 16) = 28 + 80 = 108g/mol

Percentage amount of elements in N205:

NITROGEN (N) :

(Mass of nitrogen / molar mass of N2O5) × 100%

MASS OF NITROGEN = (N2) = 2 × 14 = 28

PERCENT OF NITROGEN : (28/108) × 100%

0.259259 × 100%

= 25.925%

= 25.9%

4 0
2 years ago
According to Table I, which equation represents a change resulting in the greatest quantity of energy released?
love history [14]
The answer is 3. The releasing of energy means exothermic reaction. So the ΔH should be negative. And the greatest quantity of energy released means that the greatest number. So according to the table I, the answer is 3.
8 0
3 years ago
Read 2 more answers
HELP ASAP! Chemical reactions involving liquids only will be influenced by ALL of the following EXCEPT: a) temperature of the sy
Rom4ik [11]
<span>Chemical reactions involving only liquids will be influenced by ALL of the following EXCEPT: </span><span><span>c) size of reactant particles d) pressure of the system.

</span>Reason:
1) As per Arrhenius theory, rate of chemical reactions is influence by temperature. Mathematically it is expressed as: k = A exp(-Ea/RT)
</span>where, k = rate constant, A = collision frequency, Ea = activation energy, T = temp. From above relation, it can be seen that, chemical reactions involving only liquids will be influenced temperature.

2) Also, if know that, rates of chemical reactions is mathematically expressed as: Rate = [A]^{x} B^{y}....,
where A, B, .. are the reactants.
From above relation, it can be seen that, chemical reactions involving only liquids will be influenced concentration i.e. number of particle. 

3) However, since all the reactant and catalyst used (if any) is in liquid state, particle size of same  will not influence the reaction.

4) Also, since there are no gas-phase reactant, pressure will not affect the reaction. 
8 0
2 years ago
The combustion of palmitic acid is represented by the chemical equation: C16H32O2(s) + 23O2(g) → 16 CO2(g) + 16 H2O(l) The magni
solniwko [45]

Answer:

The correct option is C

Explanation:

From the question we are told that

The reaction is

C_{16}H_{32}O_2(g) + 23O_2(g) \to 16 CO_2(g) + 16 H_2O(l)

Generally \Delta  H  =  \Delta  U + \Delta N*  RT

Here \Delta  H is the change in enthalpy

\Delta  U is the change in the internal energy

              \Delta N  is the difference between that number of moles of product and the number of moles of reactant

Looking at the reaction we can discover that the elements that was consumed and the element that was formed is O_2 and  CO_2 and this are both gases so the change would occur in the number of moles

So  

\Delta  H  =  \Delta  U + [16 -23]*  RT

\Delta  H  =  \Delta  U -7RT

The  negative sign in the equation tell us that the enthalpy\Delta_r H would be less than the Internal energy \Delta_r U

4 0
3 years ago
Is this right????????????
zzz [600]

Answer: yea its right

Explanation:

5 0
2 years ago
Read 2 more answers
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