Answer:
Mass fraction = 0.08004
Mole fraction = 0.0377
Explanation:
Given, Mass of NaOH = 8.70 g
Mass of solution = 8.70 + 100 g = 108.70 g
= 0.08004
Molar mass of NaOH = 39.997 g/mol
The formula for the calculation of moles is shown below:
Thus,
Given, Mass of water = 100 g
Molar mass of water = 18.0153 g/mol
The formula for the calculation of moles is shown below:
Thus,
So, according to definition of mole fraction:
Atomic models were developed through indirect observation even though no one had seen an atom. There were many experiments of which I know nothing about, but in the end the scientists managed to come up with a formula and various models to describe atoms.
The
correct answer is A. In the combined gas law, if the volume is decreased and
the pressure is constant, then the temperature decreases.
<span>P1V1/
T1 = P2V2 / T2</span>
<span>Assume
the volume decrease by half; V2 = V1/2</span>
<span>P1V1/
T1 = P2V1 /2 T2</span>
<span>Cancelling
terms,</span>
<span>1/T1
= 1/2 T2</span>
T2
= T1/2
<span>Thus,
the temperature decreased.</span>
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.
