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Ymorist [56]
3 years ago
11

Calculate the heat change associated

Chemistry
1 answer:
alexgriva [62]3 years ago
7 0

Answer:

Heat change is -14,175 joules, Exothermic

Explanation:

We are given;

  • Mass of aluminium bar as 350.0 g
  • initial temperature as 70.0 °C
  • Final temperature as 25 °C

We are required to determine the heat change and indicate whether endothermic or exothermic;

We know that;

Heat change = Mass of a substance × specific heat × change in temperature

In this case;

Mass of Aluminium = 350.0 g

Change in temperature = (25 - 70)

                                       = -45° C

Specific heat of aluminium = 0.90 J/g°C

Therefore;

Heat change = 350.0 g × 0.90 J/g°C × -45°C

                     =-14,175 joules

The heat change is exothermic because it is a negative value, also because cooling process involves heat loss and thus an exothermic reaction.

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7 0
3 years ago
We have 1700 Tonnes of Amoniac every day. How many tonnes of 63% Nitrogen soda we can get?
V125BC [204]
There are 3 equations involved in manufacturing Nitric Acid from Ammonia. 

First the ammonia is oxidized:
4NH3 + 5O2 = 4NO + 6H2O

Then for the absorption of the nitrogen oxides.
2NO + O2 = N2O4

Lastly, the N2O4 is further oxidized into Nitric acid.
3N2O4 + 2H2O = 4HNO3 + 2NO

Then run stoichiometry through these equations.
The first equation produces roughly 271,722,938 grams of NO
The second equation produces roughly 416,606,944 grams of N2O4
The last equation produces roughly 380,412,294 grams of HNO3 (nitric acid)

Convert the exact number back into tons, and your answer is: 419.332775 tons.

Rounded, I'm going to say that's 419.33 tons.
Hope this helps! :)

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3 0
3 years ago
The solid form of a substance is usually more dense than its liquid and gaseous forms. Similarly the liquid form is usually more
solniwko [45]
The solid form of a substance is usually more dense than its liquid and gaseous forms. Similarly the liquid form is usually more dense than the gaseous form. Ice floating in water is an exception that breaks the general density rule. So option “A” is the correct option in regards to the given question. In case of ice formation, actually the density of water decreases by about 9%. This is the main reason behind ice floating in water. Pure water has the maximum density at 4 degree centigrade.


7 0
4 years ago
What is the empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen, and 29.0% oxygen
natta225 [31]
Carbon(C):
number of moles= mass/molar mass(Mr)
=65.5/12
=5.5 moles

Hydrogen(H):
number of moles=mass/molar mass (Mr)
=5.5/1
=5.5 moles

Oxygen (O):
number of moles = mass/molar mass (Mr)
=29.0/16
=1.8 moles

EF= lowest number of moles over each of the elements

So,
C= 5.5/1.8 = 3
H= 5.5/1.8 = 3
O= 1.8/1.8 = 1

Therefore Emperical formula= C3H3O
6 0
3 years ago
12. What is the frequency of a photon with an energy of 3.03 x 10-19 J?
bazaltina [42]

Answer:

u=4.57x10^5GHz

Explanation:

Hello.

In this case, given the formula:

E=h*u

Whereas E is the energy, h the Planck's constant and u the frequency of the photon. Thus, solving for it, we obtain:

u=\frac{E}{h}=\frac{3.03x10^{-19}J}{6.63x10^{-34}J*s}\\  \\u=4.57x10^{14}s^{-1}

Or also:

u=4.57x10^{14}Hz*\frac{1GHz}{1x10^9Hz}\\ \\u=4.57x10^5GHz

Best regards.

5 0
3 years ago
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