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zvonat [6]
3 years ago
13

List three differences between the earth 240 million years ago and the present earth.

Chemistry
1 answer:
raketka [301]3 years ago
4 0
Dinosaurs, cavemen, sabertooth tiger
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A compound is found to contain 47 percent potassium 14.5 percent carbon and 38.5 percent oxygen by the way the molar mass of the
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How does the law of conservation of mass apply to this reaction C2H4+4O2-->4H2O+2CO2 .Only the oxygen needs to be balanced B.
r-ruslan [8.4K]
C2H4+4O2-->4H2O+2CO2

the answer is C
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3 years ago
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2.0 L of a gas is at STP. What is the new pressure in kPa if the volume changes to 10.5 L and the temperature and # of molecules
Alexandra [31]

Answer:

What is the new volume if the temperature is constant? V=2.50L. P = lookPa. P2=40k Pa. V2 = x. PV = P2 ... If a sample of gas occupies 6.8 L at 327°C

5 0
3 years ago
A chemist has to prepare 250.0 mL of a 0.300 M Na2SO4(aq) solution. What mass, in grams, of sodium sulfate (formula mass 142.05
Sedbober [7]

The mass of sodium sulphate, Na₂SO₄, required to prepare the solution is 10.65 g

<h3>How to determine the mole of sodium sulphate Na₂SO₄</h3>
  • Volume = 250 mL = 250 / 1000 = 0.25 L
  • Molarity = 0.3 M
  • Mole of Na₂SO₄ =?

Mole = Molarity x Volume

Mole of Na₂SO₄ = 0.3 × 0.25

Mole of Na₂SO₄ = 0.075 mole

<h3>How to determine the mass of sodium sulphate Na₂SO₄</h3>
  • Molar mass of Na₂SO₄ = 142.05 g/mol
  • Mole of Na₂SO₄ = 0.075 mole
  • Mass of Na₂SO₄ =?

Mass = mole × molar mass

Mass of Na₂SO₄ = 0.075 × 142.05

Mass of Na₂SO₄ = 10.65 g

Thus, 10.65 g of Na₂SO₄ is needed to prepare the solution.

Learn more about molarity:

brainly.com/question/15370276

6 0
2 years ago
A compound is formed when 171.2 g of carbon reacts with 28.8 g of hydrogen. What is the mass percent of hydrogen in the compound
IgorLugansk [536]
Following the law of conservation of mass, the mass percent of hydrogen in the resulting compound is 14.4%(wt/wt). This is assuming that all of the carbon reacts with all of the hydrogen. The solution is as follows:

mass % = mass hydrogen*100/total mass = 28.8*100/(28.8+171.2) = 14.4%
4 0
3 years ago
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