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kozerog [31]
3 years ago
6

Describe at least three ways our understanding of the atom has changed. See the hint in the reference image.

Chemistry
1 answer:
abruzzese [7]3 years ago
4 0
The first model of the atom was developed by JJ Thomson in 1904, who thought that atoms were composed purely of negatively charged electrons.

This theory was then disproved by Ernest Rutherford and the gold foil experiment in 1911, where Rutherford shot alpha particles at gold foil, and noticed that some went through and some bounced back, implying the existence of a positive nucleus.

In 1926, the Austrian physicist Erwin Schrödinger created a quantum mechanical model of the atom by combining the equations for the behavior of waves with the de Broglie equation to generate a mathematical model for the distribution of electrons in an atom.
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What is the volume, in liters, of 1.40 mol of oxygen gas at 20.0°C and 0.974 atm?
topjm [15]

Answer:

V = 34.55 L

Explanation:

Given that,

No of moles, n = 1.4

Temperature, T = 20°C = 20 + 273 = 293 K

Pressure, P = 0.974 atm

We need to find the volume of the gas. It can be calculated using Ideal gas equation which is :

PV=nRT

R is gas constant, R=0.08206\ L-atm/mol-K

Finding for V,

V=\dfrac{nRT}{P}\\\\V=\dfrac{1.4\times 0.08206\times 293}{0.974 }\\\\V=34.55\ L

So, the volume of the gas is 34.55 L.

4 0
3 years ago
Without constants you would not know which variable affected the
bonufazy [111]
Two independent variables could change at the same time, and you would not know which variable affected the dependent variable
4 0
3 years ago
A solution is made by mixing 33.0 ml of ethanol, C2H6O and 67.0 ml of water. Assuming ideal behavior, what is the vapor pressure
ivann1987 [24]
Grams ethanol = 33 ml times .789 gms/ml = 26.037 gms 

<span>Moles ethanol = 26.037 gms / 46 gms/mole = .57 moles </span>

<span>Moles water = 67 ml or 67 grams/18 gms/mole = 3.22 moles </span>

<span>total moles = .57 + 3.72 = 4.29 moles </span>

<span>Mole fraction ethanol = .57 moles ethanol / 4.29 moles total = 0.13</span>

<span>Moles fraction water = 3.72 moles water / 4.29 moles total = 0.87</span>

<span>Partial pressure of ethanol = mole fraction ethanol (.13) _ times VP ethanol 43.9 torr) = 5.707 torr </span>

<span>partial pressure water = mole fraction water .87) times VP water (l7.5 torr) = 15.23 torr </span>

<span>Total vapor pressure over solution = 5.71 torr + 15.23 torr = 20.94 torr</span>
7 0
3 years ago
Which equation represents single replacement reaction? A) CH4 + 2 02 → CO2 + 2 H2O B) CaCO3 + CaO + CO2 C) 2 Na + 2 H2O → 2 NaOH
loris [4]

Answer:

C) 2 Na + 2 H2O → 2 NaOH + H2.

Explanation:

Hello there!

In this case, according to the given chemical reactions, it is possible to firstly understand that a single displacement reaction is characterized by the presence of a single element as the first reactant and a compound as the second one, thus, yielding a compound as the first product and a single element as the second one.

In such a way, according to the given choices, it possible to note that C) 2 Na + 2 H2O → 2 NaOH + H2 is the only one with the aforementioned condition as the element at the reactants side is Na and at the products side is H2.

Best regards!

6 0
3 years ago
A student is working with four beakers that each contains a clear liquid. Which set of procedures would be best to use to determ
telo118 [61]

Answer:

Observe odor, determine pH, determine density, determine boiling point

Explanation:

The correct procedures that would be best to use to determine whether a beaker contains only distilled water would be to observe the odor of the liquid in the beaker, determine the pH of the liquid, determine the density, and then determine the boiling point of the liquid.

<em>Water is generally odorless and has a pH of approximately 7 with a density of 1 kg/m3 and a boiling point of 100 </em>^oC<em>. If the liquid in the beaker ticks all these conditions, then it can be established to be only distilled water.</em>

8 0
3 years ago
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