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2 years ago

Carbon dioxide :increased or decreased why and when

1 answer:

4 0

During the day or in spring and summer, plants take up more carbon dioxide through photosynthesis than they release through respiration , and so concentrations of carbon dioxide in the air decrease. Then at night or during autumn and winter, plants reduce or even stop photosynthesising, releasing carbon dioxide back into the air. This is often called the natural carbon cycle.

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A fixed mass of oxygen gas occupies 300cm cube at 0 degree centigrade. what volume would the gas occupy at 15 degree centigrade

Luden [163]

Answer:

hey

Explanation:

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3 years ago

Which of the following is true about an ionic compound?

Genrish500 [490]

<span>D. all of the above because ionic compound is a salt. it is also held together by ionic bonds. it has anions and cations </span>

3 0

3 years ago

Read 2 more answers

What is the empirical formula?

Olenka [21]

Answer:

CH (92.2% C; 7.8% H), or just CH2

6 0

3 years ago

Aqueous sulfuric acid will react with solid sodium hydroxide to produce aqueous sodium sulfate and liquid water . Suppose 2.9 g

garri49 [273]

Answer:

1.07 g of water.

Explanation:

A reaction between an acid and a base makes water and a salt as product.

Our reaction is:

H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O

Reactants are the acid and the base. Which is the limiting?

2.9 g . 1mol /98 g = 0.0296 moles of acid

3.53 g . 1mol / 40 g = 0.088 moles of base

2 moles of base react to 1 mol of acid

0.088 moles may react to (0.088 . 1)/2 = 0.044 moles of acid

And we only have 0.0296, sulfuric acid is the limiting

Ratio is 1:2. 1 mol of acid can produce 2 moles of water.

Our 0.0296 moles may produce (0.0296 . 2) /1 = 0.0592 moles of water.

We convert moles to mass:

0.0592 mol . 18g /mol = 1.07 g

6 0

3 years ago

The half-life of a positron is very short. It reacts with an electron, and the masses of both are converted to two gamma-ray pho

sp2606 [1]

Explanation:

(a) It is known that relation between energy and mass is as follows.

$E = 2 \times mc^{2}$

where, E = energy

m = mass

c = speed of light = $3 \times 10^{8}$ m/s

As it is given that mass is $9.109 \times 10^{-31}$ kg. So, putting the given values into the above formula as follows.

$E = 2 \times mc^{2}$

= $2 \times 9.109 \times 10^{-31} kg \times 3 \times 10^{8}m/s$

= $1.638 \times 10^{-13} J$

Therefore, we can conclude that the energy produced by the reaction between one electron and one positron is $1.638 \times 10^{-13} J$ .

(b) When gamma ray photons are produced then they will have the same frequency. Relation between energy and frequency is as follows.

E = $h \times \nu$ ..... (1)

where, h = plank's constant = $6.626 \times 10^{-34} J.s$

$\nu$ = frequency

Also, $E = 2 \times mc^{2}$ ........ (2)

Hence, equating equations (1) and (2) as follows.

$h \times \nu$ = $2 \times mc^{2}$

So,

$6.626 \times 10^{-34} Js \times \nu$ = $1.638 \times 10^{-13} J$

$\nu$ = $1.236 \times 10^{20} Hz$

Thus, we can conclude that the frequency is $1.236 \times 10^{20} Hz$ .

5 0

4 years ago