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3 years ago

What is a atom of chemistry

Chemistry

1 answer:

Yuliya22 [10]3 years ago

8 0

Answer:

Atom is the smallest particle of matter.

Elements are made up of same atoms.

Atom consist of electron, proton and neutron.

Explanation:

Atom was first discovered by John Dalton.

word "Atom" came from Greek word, that means something that could not split. he explained that atom is indivisible particle.

In the end of 18th century J.J. Thomson put forward a new concept of atom. he said that atom have negative charged particles called electrons but overall atom is neutral.

In 1909 Rutherford with his students discovered positive charged particles and nucleus and said that it is in the center of atom.

He explain a model of atom and said that electrons revolve around a hard core in the center called nucleus.

In 1913 Niels Bohr explains the atomic spectra and put forward the concept of shells and sub-shells.

So overall Structure of an Atom is

consist of Neutrons in nucleus
+ve charged protons in nucleus
A -vely charged electrons revolving around the nucleus
the electron revolve in shells i.e. K, L, M, and N
Each shell divide in sub-Shell such as s, p,d and f.

Atom has a specific atomic mass and atomic number

Atomic number = number of protons or electron

Atomic mass = number of protons + number of neutrons in nucleus.

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How are carbon dioxide (CO2) levels in the atmosphere affected by tectonic uplift of rocks and their resultant chemical weatheri

valina [46]

Answer:

The levels of carbon dioxide (CO2) in the atmosphere are reduced

Explanation:

Tectonic uplift refers to the process by which the surface of the earth slowly rises either due to increasing upward force applied from the plates below the surface or decreasing downward force or weight of objects like melting glaciers acting from above. During uplift, land, as well as the sea floor rises forming mountains, plateaus and volcanic Islands.

During the process of weathering, carbon dioxide present in air combines with rainwater and forms carbonic acid. This acidic rainwater then falls on uplifted mountains and rocks weathering them in the process. Minerals present in the rock such as calcium, magnesium and sodium then combine with bicarbonate ions to form carbonates such as calcium carbonate, magnesium carbonate which are found in shells of living and dead organisms and also form rocks such as limestone. In this way, carbon dioxide is removed from the atmosphere.

7 0

3 years ago

Chlorine pentafluoride gas is collected at -17.0 °C in an evacuated flask with measured volume of 35.0 L. When all the gas has b

Svet_ta [14]

Answer:

1. The mass of Chlorine pentafluoride, ClF5, is 39.16g

2. The number of mole of Chlorine pentafluoride, ClF5, is 0.3mole

Explanation:

1. To solve the mass of Chlorine pentafluoride, ClF5, first, let us calculate the molar mass of ClF5. This is illustrated below:

Molar Mass of ClF5 = 35.5 + (5 x 19) = 35.5 + 95 = 130.5g/mol

From the ideal gas equation:

PV = nRT (1)

Recall:

Number of mole(n) = mass (m) /Molar Mass(M)

n = m/M

Now substituting the value of n in equation 1, we have:

PV = nRT

PV = mRT/M

Now we can obtain the mass of Chlorine pentafluoride ClF5 as follow:

Data obtained from the question include:

T (temperature) = -17.0 °C = - 17 + 273 = 256K

V (volume) = 35L

P (pressure) = 0.180 atm

R (gas constant) = 0.082atm.L/Kmol

m (mass of Chlorine pentafluoride) =?

M (molar mass of Chlorine pentafluoride) = 130.5g/mol

PV = mRT/M

0.180 x 35 = m x 0.082 x 256/ 130.5

Cross multiply to express in linear form as shown below:

m x 0.082 x 256 = 0.180x35x130.5

Divide both side by 0.082 x 256

m = (0.180x35x130.5) /(0.082x256)

m = 39.16g

Therefore, the mass of Chlorine pentafluoride, ClF5, is 39.16g

2. The number of mole of ClF5 can be obtained as follow:

Mass of ClF5 = 39.16g

Molar Mass of ClF5 = 130.5g/mol

Mole of ClF5 =?

Number of mole = Mass /Molar Mass

Mole of ClF5 = 39.16/130.5g

Mole of ClF5 = 0.3mole

8 0

3 years ago

Read 2 more answers

The number of neutrons in the nucleus of an atom can be determined by

Masteriza [31]

Option no. 2 subtracting the atomic number from the mass number

Example: Zn - 65 atomic weight or mass/mass number
30 atomic number

65-30 = 35 number of neutrons

5 0

3 years ago

How many liters of water must be added to 0.291 g of NaCl to create a salt water solution that has a concentration of 2.41 g/L?

dmitriy555 [2]

C=2.41 g/L
m(NaCl)=0.291 g

c=m(NaCl)/v

v=m(NaCl)/c

v=0.291/2.41= 0.1207 L = 120.7 mL

4 0

3 years ago

Read 2 more answers

Calculate the net change in enthalpy for the formation of one mole of acrylic acid from calcium carbide, water and carbon dioxid

kiruha [24]

Answer:

-471 Kj/mole acrylic acid

Explanation:

THIS IS THE COMPLETE QUESTION BELOW;

There are two steps in the usual industrial preparation of acrylic acid, the immediate precursor of several useful plastics. In the first step, calcium carbide and water react to form acetylene and calcium hydroxide: CaC (s) + 2 H2O(g) - CH (9) + Ca(OH),(s) AH -414. kJ In the second step, acetylene, carbon dioxide and water react to form acrylic acid: 6 C H (9) + 3 CO2(9) + 4H2O(g) - SCH,CHCO,H) AH-132. kJ Calculate the net change in enthalpy for the formation of one mole of acrylic acid from calcium carbide, water and carbon dioxide from these reactions. Round your answer to the nearest kJ. x 5 ?

The two equations from the reaction can be written as;

a)CaC₂(s) + 2H₂O(l) ------->C₂H₂(g) + CaOH₂(s)

Δ H= -414Kj ........................ equation (a)

b)6C₂H₂(g) +3CO₂(g)+4H₂O(g) -------> 5CH₂CHCO₂H(g) Δ H= 132Kj ...................... equation (b)

In equation (b)acrylic acid was produced by the reaction between Acetylene carbon dioxide and water

Then we can multiply equation(a) by factor of 6 and the ΔH Then we have (6× -414Kj)= ΔH= -2484Kj.

6CaC₂(s) + 12H₂O(l) ------->6C₂H₂(g) + 6CaOH₂(s)

Δ H= -2484Kj.................. equation (c)

6C₂H₂(g) +3CO₂(g)+4H₂O(g) -------> 5CH₂CHCO₂H(g) Δ H= 132Kj

Then add equation (c) and equation(b) then we have

6CaC₂(s) + 16H₂O(l)+3CO₂(g)------> 5CH₂CHCO₂H(g) + 6CaOH₂(s) ΔH= -2352Kj

ΔH(net)= -2352Kj/5moles

=-471Kj/mole

therefore, net change in enthalpy for the formation of one mole of acrylic acid from calcium carbide, water and carbon dioxide from these reactions. Round your answer to the nearest kJ. x 5 ? is -471Kj/mole acrylic acid

6 0

3 years ago