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3 years ago

After pollen lands on the stigma of a flower, which of the following happens first?

Chemistry

1 answer:

liq [111]3 years ago

4 0

The correct answer is:

Pollination

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Please help i will give 20 points

NNADVOKAT [17]

Answer:

It's A., thats conduction and its a heat transfer

Explanation:

6 0

2 years ago

The activation energy for a reaction is changed from 184 kJ/mol to 59.0 kJ/mol at 600. K by the introduction of a catalyst. If t

11111nata11111 [884]

Answer:

The catalyzed reaction will take 2.85 seconds to occur.

Explanation:

The activation energy of a reaction is given by:

$k = Ae^{-\frac{E_{a}}{RT}}$

For the reaction without catalyst we have:

$k_{1} = Ae^{-\frac{E_{a_{1}}}{RT}}$ (1)

And for the reaction with the catalyst:

$k_{2} = Ae^{-\frac{E_{a_{2}}}{RT}}$ (2)

Assuming that frequency factor (A) and the temperature (T) are constant, by dividing equation (1) with equation (2) we have:

$\frac{k_{1}}{k_{2}} = \frac{Ae^{-\frac{E_{a_{1}}}{RT}}}{Ae^{-\frac{E_{a_{2}}}{RT}}}$

$\frac{k_{1}}{k_{2}} = e^{\frac{E_{a_{2}} - E_{a_{1}}}{RT}$

$\frac{k_{1}}{k_{2}} = e^{\frac{59.0 \cdot 10^{3}J/mol - 184 \cdot 10^{3} J/mol}{8.314 J/Kmol*600 K} = 1.31 \cdot 10^{-11}$

Since the reaction rate is related to the time as follow:

$k = \frac{\Delta [R]}{t}$

And assuming that the initial concentrations ([R]) are the same, we have:

$\frac{k_{1}}{k_{2}} = \frac{\Delta [R]/t_{1}}{\Delta [R]/t_{2}}$

$\frac{k_{1}}{k_{2}} = \frac{t_{2}}{t_{1}}$

$t_{2} = t_{1}\frac{k_{1}}{k_{2}} = 6900 y*1.31 \cdot 10^{-11} = 9.04 \cdot 10^{-8} y*\frac{365 d}{1 y}*\frac{24 h}{1 d}*\frac{3600 s}{1 h} = 2.85 s$

Therefore, the catalyzed reaction will take 2.85 seconds to occur.

I hope it helps you!

4 0

3 years ago

Which of the following best summarizes the ideal gas law?

8090 [49]

Answer:

Option C. PV = nRT

Explanation:

The ideal gas gas equation gives the relationship between pressure, volume, number mole a gas and temperature of gas.

Mathematically, the ideal gas equation is given as:

PV = nRT

Where:

P is the pressure measured in atmosphere (atm).

V is the volume measured in litres(L) or cubic decimetre (dm³).

n is the number of mole of gas.

R is the gas constant (0.0821atm.L/Kmol)

T is temperature measured in Kelvin (K).

4 0

3 years ago

The pH of a solution is tested, and it is found to be a basic solution. Of the following choices, what could the pH have been? A

lesya [120]

Basic solution is pH>7
therefore the answer is D.9

8 0

2 years ago

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Which catalyzed reaction breaks up ozone? 2H2O2(l) right arrow with upper M n upper O subscript 2 above it. 2H2O(l) + O2 O3 + O

anyanavicka [17]

Answer: B

Explanation: The answer is B

6 0

2 years ago

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