All categories

3 years ago

John dalton postulated several statements about the atom. which statement did he NOT state?

Chemistry

1 answer:

algol [13]3 years ago

7 0

Answer:

The atom is divisible particle and can be subdivided into smaller particles proton, neutron and electrons was not stated by John dalton.

Explanation:

The postulate of Dalton's atomic theory that atom is indivisible particle and can not be subdivided into smaller particles was later changed because atom can be divided into neutrons, protons and electrons.

Electron:

The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.

Symbol= e⁻

Mass= 9.10938356×10⁻³¹ Kg

It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.

Proton and neutron:

While neutron and proton are present inside the nucleus. Proton has positive charge while neutron is electrically neutral. Proton is discovered by Rutherford while neutron is discovered by James Chadwick in 1932.

Symbol of proton= P⁺

Symbol of neutron= n⁰

Mass of proton=1.672623×10⁻²⁷ Kg

Mass of neutron=1.674929×10⁻²⁷ Kg

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron.

You might be interested in

Calculate the magnitude and direction (i.e., the angle with respect to the positive H-axis, measured positive as counter-clockwi

r-ruslan [8.4K]

The graphics in the attachment is part of the question, which was incomplete.

Answer: Fr = 102N and angle of approximately 11°.

Explanation: From the attachment, it is observed that from the three forces acting on M, two are perpendicular. So to find them, we have to show their x- and y- axis components. From the graph:

Fx = 70+40-10 = 100

Fy = 40-20 = 20

Now, as the forces form a triangle, the totalforce is:

Fr = $\sqrt{Fx^{2} +Fy^{2} }$

Fr = $\sqrt{10400}$

Fr = ≈ 102N

To determine the angle requested, we use:

arctg H = $\frac{Fy}{Fx}$

arctg H = $\frac{20}{100}$

H = tg 0.2 ≈ 11°.

4 0

3 years ago

Question 23

Schach [20]

Answer:

Option B. 0.136 g

Explanation:

The balanced equation for the reaction is given below:

2AgNO3(aq) + 2NaOH(aq) —> Ag2O(s) + 2NaNO3(aq) + H2O(l)

Next, we shall determine the masses of AgNO3 and NaOH that reacted and the mass of Ag2O produced from the balanced equation. This is illustrated below:

Molar mass of AgNO3 = 108 + 14 + (16x3) = 170g/mol

Mass of AgNO3 from the balanced equation = 2 x 170 = 340g

Molar mass of NaOH = 23 + 16 + 1 = 40g/mol

Mass of NaOH from the balanced equation = 2 x 40 = 80g

Molar mass of Ag2O = (108x2) + 16 = 232g/mol

Mass of Ag2O from the balanced equation = 1 x 232 = 232g

Summary:

From the balanced equation above,

340g of AgNO3 reacted with 80g of NaOH to produce 232g of Ag2O.

Next, we shall determine the limiting reactant. This can be obtained as follow:

From the balanced equation above,

340g of AgNO3 reacted with 80g of NaOH.

Therefore, 0.2g of AgNO3 will react with = (0.2 x 80)/340 = 0.047g of NaOH.

From the calculations made above, only 0.047g out of 0.2g of NaOH given, reacted completely with 0.2g of AgNO3. Therefore, AgNO3 is the limiting reactant and NaOH is the excess reactant.

Now, we can calculate the mass of Ag2O produced from the reaction of 0.2g of AgNO3 and 0.2g of NaOH.

In this case, we shall use the limiting reactant because it will produce the maximum yield of Ag2O as all of it is used up in the reaction.

The limi reactant is AgNO3 and the mass of Ag2O produced can be obtained as follow:

From the balanced equation above,

340g of AgNO3 reacted to produce 232g of Ag2O.

Therefore, 0.2g of AgNO3 will react to produce = (0.2 x 232)/340 = 0.136g of Ag2O.

Therefore, 0.136g of Ag2O was produced from the reaction.

8 0

3 years ago

A scientist has two samples of gas: The first sample contains one mole of argon atoms and has a mass of 39.948 g; the second sam

V125BC [204]

There are 6.022 × 10²³ atoms in 39.948 g of argon and 4.0026 g of helium.

Explanation:

39.945 g/mole is the molar mass of argon so 39.948 g of argon are equal to 1 mole of argon.

4.0026 g/mole is the molar mass of helium so 4.0026 g of helium are equal to 1 mole of helium.

We know that Avogadro's number tell us the number of particles in 1 mole of substance which is 6.022 × 10²³.

So in 39.948 g of argon and 4.0026 g of helium contains the same number of atoms, 6.022 × 10²³.

Learn more about:

Avogadro's number

brainly.com/question/14148121

brainly.com/question/1445383

brainly.com/question/1528951

#learnwithBrainly

4 0

3 years ago

Las Vegas, Nevada is in a desert. How does its rapid population growth affect the

Scrat [10]

Answer:

Many areas of the United States experience explosive population growth. The more people that reside someplace, the more demand there is for water there. Often these urban-growth expansions are unplanned and place extraordinary stress on the water supply system, mainly on the groundwater. The stress often depletes groundwater supply, thereby causing wells to dry up. Then water must be brought from somewhere else to support the local population.

Such situations have occurred all over the United States. For example, increased population growth in the southwestern United States has significantly lowered the water table 50 to 200 feet (depending on the area) since the 1940s. Managing urban growth, efforts to reduce water demand, conservation of the resource, and attempts to increase the water supply all address the problem of exceeding water resource limits.

Human activities affect groundwater quality.

Here are some sources and possible solutions to groundwater pollution:

Agriculture—Reduce usage of pesticides and fertilizers.

Landfills—Monitor for leakage and repair linings.

Underground storage tanks—Remove damaged and unused tanks.

Household wastes—Properly dispose of household hazardous waste.

Septic tank leaks—Properly maintain and repair tanks.

Explanation:

This came from the K12 learning course read this and the answer will be there. I underlined the important parts for the answer.

7 0

3 years ago

Which one of these is NOT a sign of chemical change? *

Gekata [30.6K]

I think it’s light
Have fun :)

3 0

3 years ago