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4 years ago

Calculate the frequency required to eject electrons from gold with a work function of 8.76 x 10-19 J

1 answer:

5 0

$hf=W+\frac{mv^{2}}{2}\\\\
f=\frac{W+\frac{mv^{2}}{2}}{h}\\\\\

W=8,76*10^{-19}J\\
m=9,11*10^{-31}kg\\
v=3*10^{8}\frac{m}{s}\\
h=6,63*10^{-34}Js\\\\\\
f=\frac{8,76*10^{-19}J+\frac{9,11*10^{-31}kg*(3*10^{8}\frac{m}{s})^{2}}{2}}{6,63*10^{-34}Js}=7,5*10^{19}Hz$

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In the reaction: C6H6 + O2 = CO2 + H2O If 26.2 grams of C6H6 is reacted in a 0.250-liter container and this reaction is carried

Lelechka [254]

<h3>Answer:</h3>

43.33 atm

<h3>Explanation:</h3>

We are given;

Mass of C₆H₆ = 26.2 g

Volume of the container = 0.25 L

Temperature = 395 K

We are required to calculate the pressure inside the container;

First, we calculate the number of moles of C₆H₆

Molar mass of C₆H₆ = 78.1118 g/mol.

But; Moles = mass ÷ Molar mass

Moles of C₆H₆ = 26.2 g ÷ 78.1118 g/mol.

= 0.335 moles C₆H₆

Second, we calculate the pressure, using the ideal gas equation;

Using the ideal gas equation, PV = nRT , Where R is the ideal gas constant, 0.082057 L.atm/mol.K

Therefore;

P = nRT ÷ V

= (0.335 mol × 0.082057 × 395 K) ÷ 0.25 L

= 43.433 atm

Therefore, the pressure inside the container is 43.33 atm

6 0

3 years ago

Where is most of the mass found in an atom

IgorLugansk [536]

massive livand that sarah or someone is how u do it

7 0

3 years ago

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Still need a good answer heterogeneous vs homogeneous, don't copy from web pls.

pantera1 [17]

Answer:

homogenous is a uniform and consistent mixture ; heterogenous is a mixture that is non-uniform

Explanation:

usually if you can separate the mixture/particles it is heterogenous. For example, pizza is heterogenous because you can separate the dough from the tomato sauce from the cheese. vinegar is homogenous (cannot separate mixture)

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3 years ago

When we put elements on the periodic table we use the______<br> mass.

vaieri [72.5K]

Answer:

They are placed on the periodic table based on their atomic number.

Explanation:

In the chemistry table, you can find the molecular mass and atomic number. Atomic number represents the number of the protons of an atom, and molecular mass represents the mass of the atom. The mass of an atom is made from proton and neutron. The element is made by arranging it based on the number of protons, which was the atomic number.

5 0

3 years ago

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A 34.0 gram sample of an un-known hydrocarbon is burned in excess oxygen to form 93.5 grams of carbon dioxide and 76.5 grams of

natka813 [3]

Answer:

The answer to your question is CH₄

Explanation:

Process

1.- Write the possible chemical reaction

CxHy + O₂ ⇒ CO₂ + H₂O

2.- Calculate the amount of carbon in the reaction

Molecular mass of CO₂ = 12 + 32 = 44 g

44 g of CO₂ ------------------- 12 g of carbon

93.5 g of CO₂ ---------------- x

x = (93.5 x 12) / 44

x = 25.5 g of carbon

3.- Calculate the mass of hydrogen in the sample

Molecular mass of water = 2 + 16 = 18 g

18 g of water ------------- 2 g of hydrogen

76.5 g of water -------- x g of hydrogen

x = (76.5 x 2) / 18

x = 8.5 g of hydrogen

4.- Calculate the moles of carbon and hydrogen in the sample

12g of carbon ------------- 1 mol

25.5g of carbon ---------- x

x = (25.5 x 1) / 12

x = 2.12 moles of carbon

1 g of hydrogen ----------- 1 mol

8.5 g of hydrogen -------- x

x = (8.5 x 1) / 1

x = 8.5 moles of hydrogen

5.- Divide both number of moles by the lowest number

carbon = 2.12 / 2.12 = 1

hydrogen = 2.12 = 8,5 / 2.12 = 4

6.- Write the molecular formula

CH₄

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3 years ago

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