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2 years ago

What does the atomic number tell you about the element

1 answer:

4 0

It tells you how many protons it has and because the number of protons =electrons it tells you also the number of electrons.

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A solution is prepared by adding 100 ml of 0.2 m hydrochloric acid to 100 ml of 0.4 m sodium formate. is this a buffer solution,

Firdavs [7]

Becoing itsodim fromate t will have pb of 67

5 0

3 years ago

Gas particles are pumped into a rigid steel container at a constant temperature. Which statement describes the change in pressur

Masteriza [31]

Answer:

The pressure inside the container would increase with each additional pump.

Explanation:

From the general gas law of ideal gases:

PV = nRT,

where, P is the pressure of the gas.

V is the volume of the gas.

n is the no. of moles of the gas.

R is the general gas constant.

T is the temperature of the gas.

As clear from the gas law; the pressure of the gas is directly proportional to the no. of moles of the gas.

P α n.

As gas particles are pumped into a rigid steel container, the no. of moles of the gas will increase.

So, the pressure of the gas will increase.

Thus, the right choice is: The pressure inside the container would increase with each additional pump.

8 0

2 years ago

Name the types of radiation known to be emitted by radioactive elements.

nikitadnepr [17]

Answer : The types of radiation known to be emitted by radioactive elements are, alpha particles, beta particles, or gamma rays.

Explanation :

Radioactive decay : It the process in which an unstable atomic nucleus loses energy by emitting the radiations like, alpha particles, beta particles, or gamma rays.

The naturally occurring radioactive elements are, radium, thorium, and uranium.

Alpha particle : It is also known as alpha radiation or alpha ray that consists of 2 protons and 2 neutrons that are bound together into a particle that is identical to the helium nucleus. It is produced in the process of alpha decay.

Beta particle : It is also known as beta radiation or beta ray. During the beta decay process, a high energy and speed electron or positron are emitted by the radioactive decay of atomic nucleus.

Gamma particle : It is also a gamma radiation or gamma ray that is arising from the radioactive decay of atomic nuclei. It has shortest wavelength waves and imparts high photon energy can pass through most forms of matters because they have no mass.

3 0

2 years ago

Molten gallium reacts with arsenic to form the semiconductor, gallium arsenide, GaAs, used in light-emitting diodes and solar ce

Vsevolod [243]

Answer:

a) 1.2g of arsenic b) 0.64g of arsenic c) 3.481g of gallium d) 3.806g of gallium e) 2.61g arsenic

Explanation:

The balanced equation is:

Ga + As = GaAs, 1:1 mole ratio

a) mass (gallium)/ molar mass of Ga = 4/ 69.723 = 0.0574mol

Mass (arsenic)/ molar mass of As = 5.5/74.9216 = 0.0734, subtracting the moles from each other (knowing already that the ratio is 1:1), arsenic is in excess by 1.2g

b) repeating the procedure (changing the values)

It will be 0.0574 to 0.06593

Arsenic is in excess by 0.00854

0.00854* mass of arsenic (such must be done for the first remaining mole) = 0.64g

c) the mole ratio is 0.0574: 0.00747

Gallium is in excess by 0.05

Mass of excess gallium = 0.05* 69.723 = 3.481g

d) using the mass given, the new ratio is

0.128: 0.0734

Gallium is in excess by 0.054mol

Mass of excess gallium = 0.054*69.723 = 3.806g

e) using the mass again, the new ratio is 0.0574: 0.02,

Gallium is in excess by 0.0374*69.723 = 2.61g

7 0

3 years ago

The solubility of nitrogen gas at 25 degrees C and 1 atm is 6.8 x 10^(-4) mol/L. If the partial pressure of nitrogen gas in air

Zolol [24]

Answer:

5.2 x 10⁻⁴ M.

Explanation:

The relationship between gas pressure and the concentration of dissolved gas is given by Henry’s law:

P = kC

where P is the partial pressure of the gaseous solute above the solution.

k is a constant (Henry’s constant).

C is the concentration of the dissolved gas.

At two different pressures, there is two different concentrations of dissolved gases and is expressed in a relation as:

P₁C₂ = P₂C₁,

P₁ = 1.0 atm, C₁ = 6.8 x 10⁻⁴ mol/L.

P₂ = 0.76 atm, C₂ = ??? mol/L.

∴ C₂ = (P₂C₁)/P₁ = (0.76 atm)(6.8 x 10⁻⁴ mol/L)/(1.0 atm) = 5.168 x 10⁻⁴ mol/L ≅ 5.2 x 10⁻⁴ M.

5 0

2 years ago