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3 years ago

Explain why plants need sunlight?

Chemistry

2 answers:

kolbaska11 [484]3 years ago

4 0

Plants need sunlight for photosynthesis.

torisob [31]3 years ago

3 0

Plants need sunlight in order to make photosynthesis.
They need it in order to make their energy, so it is basically their food source.

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Using the bond energy data from your text (or the internet), determine (show calculations for) the approximate enthalpy change ,

aleksley [76]

Answer:

∆H= 438 KJ/mol

Explanation:

First, we have to find the energy bond values for each compound:

-) Cl-Cl = 243 KJ/mol

-) F-F = 159 KJ/mol

-) F-Cl = 193 KJ/mol

If we check the reaction we can calculate the number of bonds:

$Cl_2_(_g_)~+~3F_2_(_g_)~->~2ClF_3_(_g_)$

In total we will have:

-) Cl-Cl = 1

-) F-F = 3

-) F-Cl = 6

With this in mind. we can calculate the total energy for each bond:

-) Cl-Cl = (1*243 KJ/mol) = 243 KJ/mol

-) F-F = (3*159 KJ/mol) = 477 KJ/mol

-) F-Cl = (6*193 KJ/mol) = 1158 KJ/mol

Now, we can calculate the total energy of the products and the reagents:

Reagents = 243 KJ/mol + 477 KJ/mol = 720 KJ/mol

Products = 1158 KJ/mol

Finally, to calculate the total enthalpy change we have to do a subtraction between products and reagents:

∆H= 1158 KJ/mol-720 KJ/mol = 438 KJ/mol

I hope it helps!

7 0

3 years ago

Does it take more, less, or the same amount of heat to melt 1.0 kg of ice at 0°C, or to bring 1.0 kg of liquid water at 0°C to t

Murljashka [212]

Answer : It takes less amount of heat to metal 1.0 Kg of ice.

Solution :

The process involved in this problem are :

$(1):H_2O(s)(0^oC)\rightarrow H_2O(l)(0^oC)\\\\(2):H_2O(l)(0^oC)\rightarrow H_2O(l)(100^oC)$

Now we have to calculate the amount of heat released or absorbed in both processes.

For process 1 :

$Q_1=m\times \Delta H_{fusion}$

where,

$Q_1$ = amount of heat absorbed = ?

m = mass of water or ice = 1.0 Kg

$\Delta H_{fusion}$ = enthalpy change for fusion = $3.35\times 10^5J/Kg$

Now put all the given values in $Q_1$ , we get:

$Q_1=1.0Kg\times 3.35\times 10^5J/Kg=3.35\times 10^5J$

For process 2 :

$Q_2=m\times c_{p,l}\times (T_{final}-T_{initial})$

where,

$Q_2$ = amount of heat absorbed = ?

m = mass of water = 1.0 Kg

$c_{p,l}$ = specific heat of liquid water = $4186J/Kg^oC$

$T_1$ = initial temperature = $0^oC$

$T_2$ = final temperature = $100^oC$

Now put all the given values in $Q_2$ , we get:

$Q_2=1.0Kg\times 4186J/Kg^oC\times (100-0)^oC$

$Q_2=4.186\times 10^5J$

From this we conclude that, $Q_1$ that means it takes less amount of heat to metal 1.0 Kg of ice.

Hence, the it takes less amount of heat to metal 1.0 Kg of ice.

5 0

3 years ago

Who is the father of tillage?

Katen [24]

Answer: Jethro Tull is the father of tillage and he wrote a book horse hoeing husbandry and coined the term weed and zero tillage.

Explanation:

6 0

3 years ago

3.00 moles of gas are pumped into a 1.00L rigid container with a pressure of 1.98 atm. The gas is released from the container un

guajiro [1.7K]

Answer:

1.18 moles of gas

Explanation:

3.00 moles of gas are pumped into a 1.00L rigid container with a pressure of 1.98 atm. The gas is released from the container until the pressure is 0.78 atm, how many moles of gas remain in the container?

for the sealed rigid container, the pressure is directly proportional to the amount of gas

3.00moles/1.98 atm = ? moles/0.78 atm

? = 3.00 X 0.78/1.98 =1.18 moles of gas

8 0

3 years ago

?????????????????? Why are quantities important in the study of chemistry give an example please

slamgirl [31]

Answer:

Chemistry is the study of matter and how it behaves.

The scientific method is the general process by which we learn about the natural universe.

Explanation:

8 0

3 years ago