1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Tanzania [10]
3 years ago
9

How did oxygen come up to make 21% of the earth's present atmosphere?

Chemistry
1 answer:
MakcuM [25]3 years ago
4 0
Tiny organisms known as cyanobacteria, or blue-green algae.
You might be interested in
A compound that yields hydrogen ions when dissolved in a solution
Mumz [18]

A compound that yields hydrogen ions when dissolved in a solution is an acid.

An example is an <em>aqueous solution of HCl.</em>

7 0
3 years ago
I need help with unit conversion​
saw5 [17]

Answer:

what is it?

Explanation:

you haven't said?

3 0
3 years ago
Explain the difference between a base unit and a derived unit
Scrat [10]
<span>A SI base unit is the single and direct measurement unit for a physical entity. E.g. For mass it is kg, for time it is sec, A derived unit is determined by a physical equation with the base units, like for velocity equals distance divided by time, in SI units: unit of v (velocity)= m (meter) divided by sec (seconds).

Hope this helps!</span>
3 0
3 years ago
Read 2 more answers
Why would Magnesium Phosphate (Mg3(PO4)2) not make an aqueous solution? <br><br> Please help!
netineya [11]

Answer:

Basically, all phosphates except Sodium phosphates, Potassium phosphates and Ammonium phosphates are insoluble in water. That, of course, includes Magnesium phosphate.

Explanation:

Hope this helped!

5 0
3 years ago
Read 2 more answers
Which of the following sets of empirical formula, molar mass, and molecular formula is correct?
lutik1710 [3]

Answer:

CH4N, 90g, C3H12N3

Explanation:

3 0
3 years ago
Other questions:
  • Threonine, an amino acid whose pI is 5.6, is shown below. What would be the overall charge for threonine at a pH of 5.6?
    13·1 answer
  • n atom “likes” to obtain a full outer shell. The fourth shell (in the atoms that we are studying today) can hold a maximum of 8
    9·1 answer
  • A mysterious white powder is found at a crime scene. A simple chemical analysis concludes that the powder is a mixture of sugar
    15·1 answer
  • Anybody know the java script to unblock securly???
    13·1 answer
  • Balance this equation:<br> 6K + 1Al2O3 ----&gt;<br> __K₂O+__Al
    10·1 answer
  • Given that a 15.00 g milk chocolate bar contains 9.500 g of sugar, calculate the percentage of sugar present
    8·1 answer
  • 15 15. Which two elements will form a covalent bond?
    15·1 answer
  • Solve and show work. How many grams of potassium permanganate, KMnO4 are need to make 1.25 L of 0.75 M solution?
    5·1 answer
  • All three types of worms that undergo asexual reproduction use which process?
    5·2 answers
  • Hydrogen bond is an example for? (PLEASE HELP!)
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!