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Dominik [7]
2 years ago
11

Why is light helpful? You can just give one reason

Chemistry
1 answer:
hoa [83]2 years ago
3 0
Light is helpful because it allows us to see things around us.
I hope this helps :)
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You place 36.5 ml of 0.266 M Ba(OH)2 in a coffee-cup calorimeter at 25.00°C and add 56.6 ml of 0.648 M HCl, also at 25.00°C. Aft
olya-2409 [2.1K]

Answer : The enthalpy of reaction (\Delta H_{rxn}) is, -96.9 kJ/mole

Explanation :

First we have to calculate the mass of solution.

Mass=Density\times Volume

Volume of solution = Volume of HCl + Volume of Ba(OH)_2

Volume of solution = 56.6 mL + 36.5 mL

Volume of solution = 93.1 mL

Density of solution = 1 g/mL

Mass=1g/mL\times 93.1mL=93.1g

The mass of solution is, 93.1 grams.

Now we have to calculate the heat released in the system.

Formula used :

Q=m\times c\times \Delta T

or,

Q=m\times c\times (T_2-T_1)

where,

Q = heat released = ?

m = mass = 93.1 g

C_p = specific heat capacity of water = 4.184J/g^oC

T_1 = initial temperature  = 25.0^oC

T_2 = final temperature  = 29.83^oC

Now put all the given value in the above formula, we get:

Q=93.1g\times 4.184J/g^oC\times (29.83-25.00)^ioC

Q=1881.43J=1.88kJ        (1 kJ = 1000 J)

Now we have to calculate the moles of Ba(OH)_2 and HCl.

\text{Moles of }Ba(OH)_2=\text{Concentration of }Ba(OH)_2\times \text{Volume of solution}

\text{Moles of }Ba(OH)_2=0.266M\times 0.0365L=9.71\times 10^{-3}mol

and,

\text{Moles of }HCl=\text{Concentration of }HCl\times \text{Volume of solution}

\text{Moles of }HCl=0.648M\times 0.0566L=3.66\times 10^{-2}mol

Now we have to calculate the limiting and excess reagent.

The balanced chemical reaction is,

Ba(OH)_2+2HCl\rightarrow BaCl_2+2H_2O

From the balanced reaction we conclude that

As, 1 mole of Ba(OH)_2 react with 2 mole of HCl

So, 9.71\times 10^{-3}  moles of Ba(OH)_2 react with 9.71\times 10^{-3}\times 2=0.0194 moles of HCl

From this we conclude that, HCl is an excess reagent because the given moles are greater than the required moles and Ba(OH)_2 is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of H_2O

From the reaction, we conclude that

As, 1 mole of Ba(OH)_2 react to give 2 mole of H_2O

So, 9.71\times 10^{-3}  moles of Ba(OH)_2 react with 9.71\times 10^{-3}\times 2=0.0194 moles of H_2O

Now we have to calculate the change in enthalpy of the reaction.

\Delta H_{rxn}=-\frac{q}{n}

where,

\Delta H_{rxn} = enthalpy of reaction = ?

q = heat of reaction = 1.88 kJ

n = moles of reaction = 0.0194 mole

Now put all the given values in above expression, we get:

\Delta H_{rxn}=-\frac{1.88kJ}{0.0194mole}=-96.9kJ/mole

The negative sign indicates that the heat is released.

Therefore, the enthalpy of reaction (\Delta H_{rxn}) is, -96.9 kJ/mole

3 0
3 years ago
The source of alpha particles in a smoke detector is the
pantera1 [17]

The source of alpha particles in a smoke detector is the Americium.

5 0
2 years ago
For each of the following balanced equations, calculate how many grams of each product would be produced by complete reaction of
nirvana33 [79]

Answer:

vov-nhmb-snm

come here for study boy were not allowed girl are allowed i am also girl so come for study here we only study goo.gle meet

6 0
3 years ago
How do you calculate the number of photons having a wavelength of 10.0 micrometers required to produce 1.0 kilojoules of energy
shtirl [24]

To calculate this,

We know that energy is 1 photon 
E = hc/wavelenth 
wavelength of 10.0 m 

Solution:
h = 6.626 x 10^-34 Jsec 
C = 2.9979 x 10^8 m/sec 
E = 6.626 10^-34 * 2.9979 10^8 / 10 = 1.9864 10^-26J 

Then, the number of photons is computed by:

n = 1000 / 1.9864 10^-26 = 5.04 10^28 photons 

4 0
3 years ago
What is the source of energy that is released in an exothermic reaction? what absorbs the energy that is released ?
Nadusha1986 [10]
Hello,

Here are your answers:

The proper answers to your questions are....

1. "Chemical bond energy is converted to kinetic energy"...... which causes it to release energy around its surroundings!

2. "Endothermic reactions"...... Endothermic reactions are the things that absorb the energy!

If you need anymore help feel free to ask me!

Hope this helps!
5 0
3 years ago
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