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Dimas [21]
3 years ago
8

Which scientist invented the first simple Microscope ?

Chemistry
1 answer:
Vinvika [58]3 years ago
6 0

Answer:

D.  Leeuwenhoek

Explanation:

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A container of oxygen has a volume of 30.0 mL and a pressure of 72.5 psi. If the pressure of the oxygen gas is reduced to 28 psi
OLga [1]

Answer:

THE NEW VOLUME OF THE OXYGEN GAS AT 28 PSI FROM 72.5 PSI IS 0.078 L.

Explanation:

Initial volume of the oxygen in the container = 30.0 mL = 30 / 000 L = 0.03 L

Initial pressure of the oxygen = 72.5 psi =  1 psi = 6890 pascal

Final pressure = 28 psi

Final volume = unknown

First convert the mL to L and since both pressures are in similar unit that is psi; there is no need converting them to pascal or other standard unit of pressure. They cancel each other out.

This question follows Boyle's equation of gas laws and mathematically it is written as:

P1 V1 = P2 V2

Re-arranging by making P2 the subject of the formula, we have:

V2 = P1 V1 / P2

V2 = 72,5 * 0.03 / 28

V2 = 2.175 /28

V2 = 0.0776 L

The new volume of the oxygen gas at a change in pressure from 72.5 psi to 28 psi is 0.078 L.

8 0
3 years ago
A model used for the yield Y of an agricultural crop as a function of the nitrogen level N in the soil (measured in appropriate
lisov135 [29]

Answer:

  • It is 3.

Explanation:

The model written correctly is:

  • Y=\frac{kN}{9+N^2}

This is a mathematical question, instead of a chemistry question, and you should use calculus to find the nitrogen level that gives the best yield, since this is an optimization problem.

The best yield is the maximum yield, and the maximum, provided that it exists, is found using the first derivative and making it equal to zero: Y' = 0

To find Y' you must use the quotient rule.

Y'=\frac{(kN)'(9+N^2)- (kN)(9+N^2)'}{(9+N^2)^2}\\ \\Y'=\frac{k(9+N^2)-kN(2N)}{(9+N^2)^2}\\ \\Y'=\frac{9k + kN^2 - 2kN^2}{(9 + N^2)^2}=\frac{9k-kN^2}{(9+N^2)^2}

Now make Y' = 0

  • The denominator is never equal to zero, because it is always positive and greater than 9.

  • Make the numerator equal to zero:

         9k - kN² = 0

  • Factor: k (9 - N²) = 0

  • Since k is a positve constant, it is not equal to zero, and the other factor, 9 - N², must be equal to zero:

         9 - N² = 0 ⇒ (3 - N) (3 + N) = 0

         ⇒ 3 - N = 0 or 3 + N = 0 ⇒ N = 3 or N = -3.

Since N is nitrogen level, it cannot be negative and the only valid answer is N = 3.

You can prove that it is a maximum (instead of a minimum) finding the second derivative or testing some points around 3 (e.g. 2.5 and 3.5).

8 0
3 years ago
Identify the acid and conjugate base pair in the following equation:
Serjik [45]

Answer:

hola no ablo inalgun moderador puede acabar a este otro este me borró respuesta que no debió borrar

7 0
2 years ago
Chemical formula for Potassium Hydrogen Nitrate
My name is Ann [436]

Answer:

KNO3

Explanation:

8 0
3 years ago
It is possible to have more than the maximum amount of solute dissolved in a solvent.
vladimir1956 [14]

B. False

When the maximum amount of solute has been dissolved in a given amount of solvent, we say that the solution is saturated with solute.

3 0
3 years ago
Read 2 more answers
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