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3 years ago

What do you mean by Latent heat of evaporation! (not vaporisation/fusion) Kindly tell from Science NCERT class 9.

1 answer:

4 0

Since none answered from Indian NCERT yet, let me give a simple definition from ICSE..
Latent Heat of vapourisation is the heat energy required to convert unit mass of a substance from liquid to vapour state WITHOUT ANY CHANGE IN ITS TEMPERATURE....
hope this helps!

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14. What characteristics of Earth's surface can be determined by using a topographic map?

Leno4ka [110]

The answer is letter a. Hill terrain, hill slope, and hill elevation

6 0

3 years ago

What is the stoichiometric coefficient for oxygen when the following equation is balanced using the lowest whole-number coeffici

rodikova [14]

Answer:

Option (B) 7

Explanation:

C3H6O2(l) + O2(g) → CO2(g) + H2O(l)

To know the coefficient of O2 in the above equation, let us balance the equation.

The above equation can be balance as follow:

C3H6O2(l) + O2(g) → CO2(g) + H2O(l)

There are 3 atoms of C on the left side and 1 atom on the right side. It can be balance by putting 3 in front of CO2 as shown below:

C3H6O2(l) + O2(g) → 3CO2(g) + H2O(l)

There are 6 atoms of H on the left side and 2 atoms on the right side. It can be balance by putting 3 in front of H2O as shown below:

C3H6O2(l) + O2(g) → 3CO2(g) + 3H2O(l)

There are a total of 4 atoms of O on the left side and a total of 9 atoms on the right side. It can be balance by putting 7/2 in front of O2 as show below:

C3H6O2(l) + 7/2O2(g) → 3CO2(g) + 3H2O(l)

Multiply through by 2

2C3H6O2(l) + 7O2(g) → 6CO2(g) + 6H2O(l)

Now, the equation is balanced.

From the balanced equation above, the coefficient of O2 is 7.

7 0

3 years ago

Janet dough goes to the doctor for her check up her weight is measured as 115 pounds convert this to kilograms

JulsSmile [24]

Answer:

Hi! I believe this is your answer:

52 kilograms

Hope this helps, sorry if it's wrong!

Explanation:

6 0

2 years ago

Matter and energy are

Wewaii [24]

When energy transforms into mass, the amount of energy does not remain the same. When mass transforms into energy, the amount of energy also does not remain the same. However, the amount of matter and energy remains the same. ... You would weigh much less on the Moon because it is only about one-sixth the mass of Earth. So the answer is D

3 0

3 years ago

On the basis of the information above, a buffer with a pH = 9 can best be made by using

telo118 [61]

Answer:

D H2PO4– + HPO42–

Explanation:

The acid dissociation constant for $\mathbf{H_3PO_4 , H_2PO^{-}_4 , HPO_4^{2-}}$ are $\mathbf{7\times 10^{-3}, \ \ 8\times 10^{-8} ,\ \ 5\times 10^{-13}}$ respectively.

$\mathbf{pka (H_3PO_4) = -log (7\times 10^{-3} )=2.2}$

$\mathbf{pka (H_2PO_4^-) = -log (8\times 10^{-8} )=7.1}$

$\mathbf{pka (HPO_4^{2-}) = -log (5\times 10^{-13} )=12.3}$

The reason while option D is the best answer is that, the value of pKa for both

$\mathbf{H_2PO^{-}_4 ,\ \& \ HPO_4^{2-}}$ lies on either side of the desired pH of the buffer. This implies that one is slightly over and the other is slightly under.

Using Henderson-Hasselbach equation:

$\mathbf{pH = pKa + log \Big( \dfrac{HPO_4^{2-}}{H_2PO_4^-} \Big)}$

3 0

3 years ago