Calculate the energy of a photon of electromagnetic radiation whose frequency is 2.80×1014 s−1 .

I WILL MARK YOU BRAINLIST PLEASE HELP

tekilochka [14]

Answer: See below

Explanation: a. The mass of an element is composed of:

protons: 1 amu each

neutrons: 1 amu each

electrons: 0 amu each

Only the protons and neutrons are counted in the atomic mass of an element

b. Electrons are assigned a mass of 0. They do have a mass, but it is exceedingly small compared to the protons and neutrons, so they are left out of the calculation of an element's mass.

c. An element becomes unstable if the neutrons exceed the protons by a certain ratio, dependent on the element.

7 0

2 years ago

A gas is contained in a cylinder with a volume of 2.9 L at a temperature of 32.7oC and a pressure of 645.3 torr. The gas is then

stealth61 [152]

Answer: 41 atm

Explanation:

Given that:

Original Volume of gas V1 = 2.9L

Temperature T1 = 32.7°C

Convert Celsius to Kelvin

(32.7°C + 273 = 305.7K)

Pressure P1 = 645.3 torr

New Volume V2 = 0.23 L

New temperature T2 = 894.7°C

Convert Celsius to Kelvin

(894.7°C + 273 = 1167.7K)

New pressure = ?

Then, apply the combined gas equation

(P1V1)/T1 = (P2V2)/T2

(645.3 torr x 2.9L)/305.7K = (P2 x 0.23L)/1167.7K

1871.37 / 305.7 = 0.23P2 / 1167.7

To get P2, Cross multiply

1871.37 x 1167.7 = 305.7 x 0.23P2

2185198.749 = 70.311P2

Divide both sides by 70.311

2185198.749/70.311 = 70.311P2/70.311

31079.045 torr = P2

Now, convert pressure in torr to atmosphere

Since 760 torr = 1 atm

31079.045 torr = Z

cross multiply

760 torr x Z = 31079.045 torr x 1 atm

Z = 31079.045 torr / 760 torr

Z = 40.89 atm (Round to the nearest whole number as 41 atm)

Thus, new pressure of gas is 41 atm

3 0

2 years ago

Why do we call meteors shooting stars?

zlopas [31]

They burn up and cause it to look like shooting stars

6 0

3 years ago

How did rutherford know that the nucleus was positively charged?

AleksAgata [21]

'cause alphe-particle which was +ve charge, get repulsion from the atom, so he deducted that.......

3 0

3 years ago

Assinale a alternativa incorreta. *

MakcuM [25]

Answer:

The incorrect choice is the last one:

In the Leucipo and Democritus atomic model, electrons had negative charges.

Explanation:

The translation of the question is:

Choose the incorrect statement. *

Matter is everything that has mass and occupies volume.

Mass and weight are different quantities. Mass is a measure of how much matter an object has, and weight is a measure of the gravitational pull force suffered by the object.

Dalton's atomic model has similarities to the atomic model described by Leucipo and Democritus.

Dalton thought that atoms of the same element could not combine, as they developed mutual repulsion.

In the Leucipo and Democritus atomic model, electrons had negative charges.

<h2>Solution</h2>

The last statement is false because Leucipo and Democritus thought that the atom was an indivisible particle. This is, they did not think there were subatomic particles, such as electrons. Furthermore, the idea of a particle with a negative charge was developed much time (centuries) later.

As for the other statements:

Matter is everything that has mass and occupies volume: this is the current definition of matter; for instance, wood, air, atoms, have mass and occupy volume. Thougths, feelings do not have either mass or occupy a volume, they are not matter.

Mass and weight are different quantities. Mass is a measure of how much matter an object has, and weight is a measure of the gravitational pull force suffered by the object. Indeed, the mass is determined by the number of atoms of the substance, but weight is the force of attraction from Earth (or other planet, if the object is in other planet). Mass does not change with the location; weight does.

Dalton's atomic model has similarities to the atomic model described by Leucipo and Democritus: sure. This is a hystorical question. Leucippus and Democritus were two Greek phylosophers who believed that the matter was formed by tiny solid particles, the atom.

Dalton thought that atoms of the same element could not combine, as they developed mutual repulsion. In the times of Dalton, when he developed the law of multiple proportions, atoms of a same kind were thought to repel each other.

3 0

3 years ago