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Simora [160]
3 years ago
15

What was the oxygen crisis

Chemistry
1 answer:
salantis [7]3 years ago
8 0
The Great Oxidation Event (GOE), sometimes also called the Great Oxygenation Event, Oxygen Catastrophe, Oxygen Crisis, Oxygen Holocaust,[2] or Oxygen Revolution, was a time period when the Earth's atmosphere and the shallow ocean first experienced a rise in oxygen, approximately 2.4 billion years ago (2.4 Ga) to 2.1–2.0 Ga during the Paleoproterozoic era.[3] Geological, isotopic, and chemical evidence suggests that biologically produced molecular oxygen (dioxygen, O2) started to accumulate in Earth's atmosphere and changed Earth's atmosphere from a weakly reducing atmosphere to an oxidizing atmosphere,[4] causing many existing species on Earth to die out.[5] The cyanobacteria producing the oxygen caused the event which enabled the subsequent development of multicellular forms.
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What is the net ionic charge of a calcium ion?
vaieri [72.5K]

Answer:

Ca generally loses two electrons from its outer shell to form a Ca2+ ion.

5 0
3 years ago
A 200. gram sample of a salt solution contains 0.050 grams of NaCl. What is the concentration of the
wariber [46]

Answer:

2.5 × 10² ppm

Explanation:

Step 1: Given data

  • Mass of NaCl: 0.050 g
  • Mass of the sample: 200. g

Step 2: Convert 0.050 g to μg

We will use the conversion factor 1 g = 10⁶ μg.

0.050 g × 10⁶ μg/1 g = 5.0 × 10⁴ μg

Step 3: Calculate the concentration of NaCl in ppm

The concentration of NaCl in ppm is equal to the micrograms of NaCl per gram of the sample.

5.0 × 10⁴ μg NaCl/200. g = 2.5 × 10² ppm

3 0
3 years ago
An atom has a mass number of 25 and 13 neutrons. what is the atomic number of this atom? express your answer as an integer.
Snowcat [4.5K]
13 because an atom has the same number of protons as neutrons
5 0
3 years ago
I NEED HELP PLEASE, THANKS!
ira [324]

Answer:

About 0.652

Explanation:

Because the reaction is balanced, we can go straight to the next step. The molar mass of potassium is about 39.098, while the molar mass of hydrogen gas is 2 and the molar mass of water is 18. Therefore, 25.5g of potassium would be about 0.652 moles, and 220 grams of water would be about 12.222 moles, making potassium the limiting reactant. Since there is a single unit of each compound on both sides of the equation, there would be an equal amount of moles of potassium and hydrogen, and therefore about 0.652 moles of hydrogen gas would be produced. Hope this helps!

6 0
2 years ago
An air bubble with a volume of 5.0 ml is released at the bottom of a lake where the pressure is 3.0 atm. when it reaches the sur
Svetradugi [14.3K]

The new volume of the air bubble that has an initial volume of 5.0 ml released at the bottom of a lake where the pressure is 3.0 atm is 15mL.

<h3>How to calculate volume?</h3>

The volume of a given gas can be calculated by using the following formula:

P1V1 = P2V2

Where;

  • P1 = initial pressure
  • V1 = initial volume
  • P2 = final pressure
  • V2 = final volume

5 × 3 = 1 × V2

15 = V2

V2 = 15mL

Therefore, the new volume of the air bubble that has an initial volume of 5.0 ml released at the bottom of a lake where the pressure is 3.0 atm is 15mL.

Learn more about volume at: brainly.com/question/1578538

7 0
2 years ago
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