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tamaranim1 [39]
3 years ago
14

Which is an example of an endothermic reaction? A. combustion of fuels B. burning of wood C. cellular respiration D. photosynthe

sis E. nuclear explosion
Chemistry
2 answers:
kifflom [539]3 years ago
8 0

D. photosynthesis is an endothermic reaction

grandymaker [24]3 years ago
6 0

Answer: D. photosynthesis

Explanation:

Exothermic processes are those processes in which heat is released and endothermic processes are those processes in which heat is absorbed.

A. Combustion of fuels is an oxidation of hydrocarbons where energy is released.

B. Burning of wood is oxidation of carbon in which energy is released.

C. Cellular respiration is oxidation of food to release energy as ATP.

D. Photosynthesis is process of generation of food by green plants by use of sunlight as energy source.

E. Nuclear explosion involves nuclear reactions in which energy is released.

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I need help with this :/
uranmaximum [27]
Ok please tell me what exactly you need help with

6 0
3 years ago
(b)
pentagon [3]

8%

Explanation:

In a DNA molecule the no. of Adenine bases equal to that of Thymine bases

The no. of Cytosine bases equal to that of Guamine bases.

If we take no. of Thymine bases as x and no. of Cytosine bases as y,

Adenine + Thymine + Cytosine + Guamine = 100

x + x + y+y = 100

2( x+y) = 100

x+y = 50

y=42

therefore x= 50-42 = 8%

4 0
2 years ago
The reaction is proceeding at a rate of 0.0080 Ms-1 in 50.0 mL of solution in a system with unknown concentrations of A and B. W
Leokris [45]

Answer:

0.0010 mol·L⁻¹s⁻¹  

Explanation:

Assume the rate law is  

rate = k[A][B]²

If you are comparing two rates,

\dfrac{\text{rate}_{2}}{\text{rate}_{1}} = \dfrac{k_{2}\text{[A]}_2[\text{B]}_{2}^{2}}{k_{1}\text{[A]}_1[\text{B]}_{1}^{2}}= \left (\dfrac{\text{[A]}_{2}}{\text{[A]}_{1}}\right ) \left (\dfrac{\text{[B]}_{2}}{\text{[B]}_{1}}\right )^{2}

You are cutting each concentration in half, so

\dfrac{\text{[A]}_{2}}{\text{[A]}_{1}} = \dfrac{1}{2}\text{ and }\dfrac{\text{[B]}_{2}}{\text{[B]}_{1}}= \dfrac{1}{2}

Then,

\dfrac{\text{rate}_{2}}{\text{rate}_{1}} = \left (\dfrac{1}{2}\right ) \left (\dfrac{1}{2}\right )^{2} = \dfrac{1}{2}\times\dfrac{1}{4} = \dfrac{1}{8}\\\\\text{rate}_{2} = \dfrac{1}{8}\times \text{rate}_{1}= \dfrac{1}{8}\times \text{0.0080 mol$\cdot$L$^{-1}$s$^{-1}$} = \textbf{0.0010 mol$\cdot$L$^{-1}$s$^{-1}$}\\\\\text{The new rate is $\large \boxed{\textbf{0.0010 mol$\cdot$L$^\mathbf{{-1}}$s$^{\mathbf{-1}}$}}$}

8 0
3 years ago
Which part of a light microscope focuses light onto the specimen through the lens?
finlep [7]
I think its the mirror because condenser helps in allowing the amount of light to pass.
5 0
4 years ago
Yasmin's teacher asks her to make a supersaturated saline solution. Her teacher tells her that the solubility of the salt is 360
Aleks [24]

Answer:

She can add 380 g of salt to 1 L of hot water (75 °C) and stir until all the salt dissolves. Then, she can carefully cool the solution to room temperature.  

Explanation:

A supersaturated solution contains more salt than it can normally hold at a given temperature.

A saturated solution at 25 °C contains 360 g of salt per litre, and water at 70 °C can hold more salt.

Yasmin can dissolve 380 g of salt in 1 L of water at 70 °C. Then she can carefully cool the solution to 25 °C, and she will have a supersaturated solution.

B and D are wrong. The most salt that will dissolve at 25 °C is 360 g. She will have a saturated solution.

C is wrong. Only 356 g of salt will dissolve at 5 °C, so that's what Yasmin will have in her solution at 25 °C. She will have a dilute solution.

3 0
3 years ago
Read 2 more answers
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