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almond37 [142]
3 years ago
7

How many atoms are in 20 grams of aluminum ​

Chemistry
1 answer:
jeyben [28]3 years ago
5 0

Answer:

4.5 × 10²³ number of atoms Al

Explanation:

Given data:

Mass of Al = 20 g

Number of atoms of Al = ?

Solution:

The given problem will solve by using Avogadro number.

'It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance" .The number 6.022 × 10²³ is called Avogadro number.

We will calculate  the number of moles of Al first:

Number of moles = mass/molar mass

Number of moles = 20 g/ 27 g/mol

Number of moles = 0.74 mol

1 mole = 6.022 × 10²³ number of atoms

0.74 mol ×  6.022 × 10²³ number of atoms / 1 mol

4.5 × 10²³ number of atoms Al

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The naturally occurring radioactive decay series that begins with 23592U stops with formation of the stable 20782Pb nucleus. The
dsp73

Answer: There are 7 alpha-particle emissions and 4 beta-particle emissions involved in this series

Explanation:

Alpha Decay: In this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. The mass number is reduced by 4 units and atomic number is reduced by 2 units.

Beta Decay : It is a type of decay process, in which a proton gets converted to neutron and an electron. This is also known as -decay. In this the mass number remains same but the atomic number is increased by 1.

In radioactive decay the sum of atomic number or mass number of reactants must be equal to the sum of atomic number or mass number of products .

_{92}^{235}\textrm{U}\rightarrow _{82}^{207}\textrm{Pb}+X_2^4\alpha+Y_{-1}^0e

Thus for mass number : 235 = 207+4X

4X= 28

X = 7

Thus for atomic number : 92 = 82+2X-Y

2X- Y = 10

2(7) - Y= 10

14-10 = Y

Y= 4

_{92}^{235}\textrm{U}\rightarrow _{82}^{207}\textrm{Pb}+7_2^4\alpha+4_{-1}^0e

Thus there are 7 alpha-particle emissions and 4 beta-particle emissions involved in this series

3 0
3 years ago
The specific heat of gold is 0.031 calories/gram°C. If 10.0 grams of gold were heated and the temperature of the sample
IgorLugansk [536]

Answer:

6.2 calories

Explanation:

Data Given:

change in temperature = 20 °C

specific heat of gold = 0.031 calories/gram °C

mass of gold = 10.0 grams

Amount of Heat = ?

Solution:

Formula used

             Q = Cs.m.ΔT

Where:

Q = amount of heat

Cs = specific heat of gold = 0.031 calories/gram °C

m = mass

ΔT = Change in temperature

Put values in above equation

                Q = 0.031 calories/gram °C x 10.0 g x 20 °C

                Q = 6.2 calories

So option A is correct = 6.2 calories

6 0
3 years ago
What is the balanced form of the chemical equation shown below?
Svetradugi [14.3K]

Answer:

D

Explanation:

Double Displacement reaction

Both sides are balanced with option D

3 0
3 years ago
A magnet moved near a coil of wire can cause a(n)
Phantasy [73]
When a magnet moves near a coil of wire it can cause an A. electric current
7 0
4 years ago
Read 2 more answers
What volume of oxygen (in L) is produced
sveticcg [70]

Answer:

12.36 L.

Explanation:

We'll begin by calculating the number of mole in 147.1 g of lead(II) nitrate, Pb(NO₃)₂. This can be obtained as follow:

Molar mass of Pb(NO₃)₂ = 207.2 + 2[14.01 + (16×3)]

= 207.2 + 2[14.01 + 48]

= 207.2 + 2[62.01]

= 207.2 + 124.02

= 331.22 g/mol

Mass of Pb(NO₃)₂ = 147.1 g

Mole of Pb(NO₃)₂ =?

Mole = mass / Molar mass

Mole of Pb(NO₃)₂ = 147.1 / 331.22

Mole of Pb(NO₃)₂ = 1.104 moles.

Next, we shall determine the number of mole of oxygen gas, O₂, produce from the reaction. This can be obtained as follow:

2Pb(NO₃)₂ —> 2PbO + 4NO₂ + O₂

From the balanced equation above,

2 moles of Pb(NO₃)₂ decomposed to produce 1 mole of O₂.

Therefore, 1.104 moles of Pb(NO₃)₂ will decompose to produce = (1.104 × 1)/2 = 0.552 mole of O₂.

Finally, we shall determine the volume occupied by 0.552 mole of oxygen gas, O₂. This can be obtained as follow:

1 mole of O₂ occupied 22.4 L at STP.

Therefore, 0.552 mole of O₂ will occupy = 0.552 × 22.4 = 12.36 L at STP.

Thus, the volume of oxygen gas, O₂ produced is 12.36 L.

6 0
3 years ago
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