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timofeeve [1]
3 years ago
10

BRAINLIESTTT ASAP!! PLEASE HELP ME :)

Chemistry
1 answer:
alexandr402 [8]3 years ago
3 0

Physical change is the change we can see with our eyes. Chemical change is the change that we cannot see. Examples: physical change: The Polar ice caps are melting, and we can see that as it happens. Chemical change: The cooking of an egg or some combustion, like a fire. We can't see the chemicals coming from the fire, but there are chemicals coming from what is being burned and is being released into the air that we cannot see.

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A compound is found to be 30.45% n and 69.55 % o by mass. if 1.63 g of this compound occupy 389 ml at 0.00°c and 775 mm hg, what
Charra [1.4K]
1) mass composition

N: 30.45%
O: 69.55%
   -----------
   100.00%

2) molar composition

Divide each element by its atomic mass

N: 30.45 / 14.00 = 2.175 mol

O: 69.55 / 16.00 = 4.346875

4) Find the smallest molar proportion

Divide both by the smaller number

N: 2.175 / 2.175 = 1

O: 4.346875 / 2.175 = 1.999 = 2

5) Empirical formula: NO2

6) mass of the empirical formula

14.00 + 2 * 16.00 = 46.00 g

7) Find the number of moles of the gas using the equation pV = nRT

=> n = pV / RT = (775/760) atm * 0.389 l / (0.0821 atm*l /K*mol * 273.15K)

=> n = 0.01769 moles

8) Find molar mass

molar mass = mass in grams / number of moles = 1.63 g / 0.01769 mol = 92.14 g / mol

9) Find how many times the mass of the empirical formula is contained in the molar mass

92.14 / 46.00 = 2.00

10) Multiply the subscripts of the empirical formula by the number found in the previous step

=> N2O4

Answer: N2O4
3 0
3 years ago
Compared to other stars we observe, the Sun appears bigger and brighter because:
Kipish [7]

Answer:

Compared to other stars we observe, the Sun appears bigger and brighter because it is much closer to earth.

Objects closer to earth appear to be much bigger and brighter.

Let me know if this helps!

3 0
2 years ago
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The _______ energy from the _______ arrives in the form of visible and invisible light. A. Earth's, Sun B. Moon's, Earth C. Sun'
wlad13 [49]
The correct answer is C the suns energy from the earth
3 0
3 years ago
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A reaction has a forward rate constant of 2.3 × 106 s-1 and an equilibrium constant of 4.0 × 108. what is the rate constant for
avanturin [10]
Answer is: 5,75·10⁻¹.
Kf = 2,3·10⁶ 1/s.
K = 4,0·10⁸ 1/s.
Kr = ?
Kf - <span>forward rate constant.
K - </span><span>equilibrium constant.
Kr - </span><span>reverse rate constant.
</span>Since both Kf and Kr are constants at a given temperature, their ratio is also a constant that is equal to the equilibrium constant K.<span>
K = Kf/Kr.
Kr = Kf/K = </span>2,3·10⁶ 1/s ÷ 4,0·10⁸ 1/s = 5,75·10⁻¹.

5 0
3 years ago
What are the 5 steps in nuclear production​
ira [324]

The first step is splitting the atoms. Then there are control rods that absorb free floating nerons that are a result of fission. Next they heat they water pipe. Finally when they heat the pipe and water it turns to steam and they use it to harness energy!

6 0
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