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1 year ago

Why would early Earth have been toxic for modern day animals? Why were cyanobacteria able to

Chemistry

1 answer:

Oksanka [162]1 year ago

5 0

Answer: The surface of early earth was mostly molten and volcanic. The atmosphere was hot and highly toxic.

Explanation: Photosynthetic organisms were present when earth was primarily anoxic. photosynthetic organisms were present when earth was primarily anoxic. the early forms of photosynthesis did not produce oxygen as a waste product. cyanobacteria carry out anoxic photosynthesis. the early forms of photosynthesis did produce oxygen, but it was not enough to make a difference in the atmosphere. the early forms of photosynthesis were carried out in the water, and there was no way for the oxygen to move into the atmosphere.

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A 100 mL reaction vessel initially contains 2.60×10^-2 moles of NO and 1.30×10^-2 moles of H2. At equilibrium the concentration

Sliva [168]

Answer:

<h2>The equilibrium constant Kc for this reaction is 19.4760</h2>

Explanation:

The volume of vessel used= $100$ ml

Initial moles of NO= $\frac{2.60}{10^2}$ moles

Initial moles of H2= $\frac{1.30}{10^2}$ moles

Concentration of NO at equilibrium= $0.161$ M

$Concentration(in M)=\frac{moles}{volume(in litre)}$

Moles of NO at equilibrium= $0.161(\frac{100}{1000})$

= $\frac{1.61}{10^2}$ moles

2H2 (g) + 2NO(g) <—> 2H2O (g) + N2 (g)

<u>Initial</u> :1.3*10^-2 2.6*10^-2 0 0 moles

<u>Equilibrium</u>:1.3*10^-2 - x 2.6*10^-2-x x x/2 moles

∴ $\frac{2.60}{10^2}-x=\frac{1.61}{10^2}$

⇒ $x=\frac{0.99}{10^2}$

$Kc=\frac{[H2O]^2[N2]}{[H2]^2[NO]^2} (volume of vesselin litre)$

<u>Equilibrium</u>:0.31*10^-2 1.61*10^-2 0.99*10^-2 0.495*10^-2 moles

⇒ $Kc=\frac{(0.0099)^2(0.00495)}{(0.0031)^2(0.0161)^2} (0.1)$

⇒ $Kc=19.4760$

3 0

2 years ago

A compound that is composed of carbon, hydrogen, and oxygen contains 70.6% C, 5.9% H, and 23.5% O by mass. The molecular weight

zhannawk [14.2K]

Answer: The molecular formula will be $C_8H_8O_2$

Explanation:

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of C= 70.6 g

Mass of H = 5.9 g

Mass of O = 23.5 g

Step 1 : convert given masses into moles.

Moles of C = $\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{70.6g}{12g/mole}=5.9moles$

Moles of H = $\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{5.9g}{1g/mole}=5.9moles$

Moles of O = $\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{23.5g}{16g/mole}=1.5moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = $\frac{5.9}{1.5}=4$

For H = $\frac{5.9}{1.5}=4$

For O = $\frac{1.5}{1.5}=1$

The ratio of C : H: O= 4: 4:1

Hence the empirical formula is $C_4H_4O$

The empirical weight of $C_4H_4O$ = 4(12)+4(1)+1(16)= 68g.

The molecular weight = 136 g/mole

Now we have to calculate the molecular formula.

$n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{136}{68}=2$

The molecular formula will be= $2\times C_4H_4O=C_8H_8O_2$

4 0

2 years ago

When 100 ml of 1.0 M Na3PO4 is mixed with 100 ml of 1.0 M AgNO3,a yellow precipitate forms and Ag+ becomes negligibly small. Whi

jok3333 [9.3K]

Answer:

Option A

Explanation:

Number of millimoles of Na3PO4 = 1 × 100 = 100

Number of millimoles of AgNO3 = 1 × 100 = 100

When 1 mole of Na3PO4 is dissociated we get 3 moles of sodium ions and 1 mole of phosphate ion

When 1 mole of AgNO3 is dissociated, we get 1 mole of Ag+ and 1 mole of NO3-

As Ag+ concentration is negligible, the dissociated Ag+ ion must have form the precipitate with phosphate ion and as number of moles of Ag+ and phosphate ion are same, therefore the concentration of phosphate ion must be negligible

Here as 100 millimoles of Na3PO4 is there, we get 300 millimoles of Na+ and 100 millimoles of PO43-

And as 100 millimoles of AgNO3 is there, we get 100 millimoles of Ag+ and 100 millimoles of NO3-

∴ Increasing order of concentration will be PO43- < NO3- < Na+

4 0

2 years ago

Read 2 more answers

A mass of chemicals contains 100 units of potential energy. after an explosion, all the chemical energy is converted into therma

tester [92]

<span>According to the law of conservation of energy and due that all the chemical energy is converted to other three types of energy, the total sum of these three energies after the explosion must be the same than the initial energy, that is 100 units.</span>

8 0

2 years ago

An object accelerates 12.0 m/s2 when a force of 6.0 newtons is applied to it. What is the mass of the object?

dedylja [7]

Answer:

The mass of object is 0.5 Kg.

Explanation:

Given data:

Acceleration of object = 12.0 m/s²

Force on object = 6.0 N

Mass of object = ?

Solution:

Formula:

F = m×a

F = force

m = mass

a = acceleration

Now we will put the values in formula.

6.0 N = m × 12.0 m/s²

m = 6.0 N / 12.0 m/s²

( N = kg.m/s²)

m = 0.5 kg

The mass of object is 0.5 Kg.

5 0

2 years ago