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Eva8 [605]
3 years ago
7

How many protons and neutrons does Polonium-211 have?​

Chemistry
1 answer:
Stells [14]3 years ago
3 0

Answer:

Protons: 84

Neutrons: 127

Explanation:

The number of protons is the atomic number. The number of neutrons can be found by subtracting the proton number (84) from the isotope number (211)

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A 22.0 mLmL sample of a 1.16 MM potassium sulfate solution is mixed with 14.8 mLmL of a 0.860 MM barium nitrate solution and thi
dezoksy [38]

Answer:

The limiting reactant is Ba(NO3)2

The theoretical yield BaSO4 is 2.97 grams

The percent yield of the reaction is 86.5 %

Explanation:

Step 1: Data given

Volume of a 1.16 M potassium sulfate solution (K2SO4) = 22.0 mL = 0.022 L

Volume of a 0.860 M barium nitrate solution (Ba(NO3)2 = 14.8 mL = 0.0148 L

The solid BaSO4 is collected, dried, and found to have a mass of 2.57 grams

Step 2: The balanced equation

K2SO4(aq) + Ba(NO3)2(aq) → BaSO4(s) + 2KNO3(aq)

Step 3: Calculate moles

Moles = volume * molarity

Moles K2SO4 = 0.022 L * 1.16 M

Moles K2SO4 = 0.02552 moles

Moles Ba(NO3)2 = 0.0148 L * 0.860 M

Moles Ba(NO3)2 = 0.012728 moles

Step 4: Calculate the limiting reactant

For 1 mol K2SO4 we need 1 mol Ba(NO3)2 to produce 1 mol BaSO4 and 2 moles KNO3

Ba(NO3)2 is the limiting reactant. It will completely be consumed. (0.012728 moles) . K2SO4 is in excess. There will remain 0.02552 - 0.012728 = 0.012792 moles

Step 5: Calculate moles BaSO4

‬For 1 mol K2SO4 we need 1 mol Ba(NO3)2 to produce 1 mol BaSO4 and 2 moles KNO3

For 0.012728 moles Ba(NO3)2 we'll have 0.012728 moles BaSO4

Step 6: Calculate mass BaSO4

Mass BasO4 = moles BaSO4 * molar mass BaSO4

Mass BaSO4 =  0.012728 moles *  233.38 g/mol

Mass BaSO4 = 2.97 grams

Step 7: Calculate the percent yield

% yield = (actual yield / theoretical yield ) * 100 %

% yield = ( 2.57 grams / 2.97 grams ) * 100 %

% yield = 86.5 %

The limiting reactant is Ba(NO3)2

The theoretical yield BaSO4 is 2.97 grams

The percent yield of the reaction is 86.5 %

7 0
3 years ago
1. Which of the following metals oxidized by calcium ions?
viktelen [127]

1 A

2 B

3 B

4 A

5 B

6 D

7 D

8 B

8 0
3 years ago
An X-ray beam with λ = 157 pm incident on the surface of a crystal produced a maximum reflection at an angle of θ = 28.5 ∘. Assu
WARRIOR [948]

Answer:

The separation between layers of atoms in the crystal is 164.52 pm.

Explanation:

Formula used

n \lambda = 2d\sin \theta (Bragg's law)

Where :

n = an order of reflection (integer)

\lambda = wavelength of the beam incident X-ray

d = spacing between the layer

θ = incident angle ( angle between ray and scatter plane)

We have :

λ = 157 pm

θ = 28.5°

n = 1

d = ?

1\times 157 pm= 2d\sin (28.5^o) (Bragg's law)

d=\frac{1\times 157 pm}{2\times \sin (28.5^o)}=164.52 pm

The separation between layers of atoms in the crystal is 164.52 pm.

8 0
3 years ago
what are two or more substances that are together in the same place, but are not chemically combined in a set ratio. They can be
GuDViN [60]
Yahoo has the answer to that question. because i looked it up on yahoo..
6 0
2 years ago
Nguyên tố A có cấu hình electron phân lớp cuối cùng là 4p3. A phải
Studentka2010 [4]

Answer: ?

Explanation: I translated this and It makes no sense.

Tôi đã dịch điều này và nó không có ý nghĩa.

4 0
2 years ago
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