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ELEN [110]
3 years ago
15

FOR REAL HELPPPPP!!!!

Chemistry
1 answer:
IgorLugansk [536]3 years ago
6 0

Answer:

I belive the answer is gases, liquids, and solids.

Explanation:

The reason I say this is because a vacuum is an empty void of space and time, nothing is there so I believe no sound should be able to penetrate through it.

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Which best describes a compound such as sodium chloride?
My name is Ann [436]

Answer:

i think it is the last option a pure substance that can be separated into different elements by chemical means

Explanation:

4 0
3 years ago
Read 2 more answers
In a coffee cup calorimeter, 1.60 g of NH4NO3 is mixed with 75.0 g of water at an initial temperature of 25.00 degrees C. After
igomit [66]

Answer:

+26.6kJ/mol

Explanation:

The enthalpy of dissolution of NH₄NO₃ is:

NH₄NO₃(aq) + ΔH  → NH₄⁺ + NO₃⁻

Where ΔH is the heat of reaction that is absorbed per mole of NH₄NO₃,

The moles that reacts in 1.60g are (Molar mass NH₄NO₃:80g/mol):

1.60g * * (1mol / 80g) = 0.02 moles reacts

To find the heat released in the coffee cup calorimeter, we must use the equation:

Q = m×ΔT×C

Where Q is heat released,

m is mass of the solution

ΔT is change in temperature (Final temperature - Initial temperature)

C is specific heat of the solution (4.18J/g°C)

Mass of the solution is:

1.60g + 75g = 76.60g

Change in temperature is:

25.00°C - 23.34°C = 1.66°C

Replacing:

Q = m×ΔT×C

Q = 76.60g×1.66°C×4.18J/g°C

Q = 531.5J

This is the heat released per 0.02mol. The heat released per mole (Enthalpy change for the dissolution of NH₄NO₃) is:

531.5J / 0.02mol = 26576J/ mol =

+26.6kJ/mol

<em>+ because the heat is absorbed, the reaction is endothermic-</em>

7 0
3 years ago
What causes pressure inside a helium balloon?
kupik [55]

Explanation:

So the gas pressure of a helium balloon arises from the impact of the collisions of the helium atoms between themselves and with the inside surface of the balloon. Of course, the outside atmosphere similarly exerts a pressure on the outside of the balloon.

7 0
3 years ago
Write the balanced half equation of iron 2 and permanganate in a solution of acid. Show all of your work.
Aleks [24]

Answer:

5Fe⁺² + MnO₄⁻ + 8H⁺ => 5Fe⁺³ + Mn⁺² + 4H₂O

Explanation:

Fe⁺² + MnO₄⁻ +  H⁺ => Mn⁺² + Fe⁺³ +  H₂O

5(Fe⁺² => Fe⁺³ + 1e⁻)      =>                        5Fe⁺² => 5Fe⁺³ + 5e⁻

<u>MnO₄⁻ + 5e⁻ => Mn⁺²    =>   MnO₄⁻ + 8H⁺ + 5e⁻ => Mn⁺² + 4H₂O</u>

                                      =>  5Fe⁺² + MnO₄⁻ + 8H⁺ => 5Fe⁺³ + Mn⁺² + 4H₂O

6 0
3 years ago
How many half-lives will pass by the time 1.56% of I-131 is present? B. Approximately how many days does that equal? *
serg [7]

Answer: Hmmmmm that's crazy....

There are a couple of equations one could use for this type of problem, but I find the following to be the easiest to use and to understand.

Fraction remaining (FR) = 0.5n

n = number of half lives that have elapsed

In this problem, we need to find n and are given the FR, which is 1.56% or 0.0156 (as a fraction).

0.0156 = 0.5n

log 0.0156 = n log 0.5

-1.81 = -0.301 n

n = 6.0 half lives have elapsed

Explanation:

Just wanted to help. Hopefully it's correct wouldn't want to waster your time ;)

6 0
2 years ago
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