Answer:
The answer to your question is: The mass number will be 4 units lower.
Explanation:
Alpha particles are Helium atoms, which have a mass number of 4 and atomic number of 2.
When an alpha particle is released, the original atom loses 2 protons and and 2 neutrons an we can see in the example.
²²⁶ ₈₈ Ra ⇒ ²²² ₈₆ Rn + ⁴₂ He
1.905 moles of Helium gas are in the tube. Hence, option A is correct.
<h3>What is an ideal gas equation?</h3>
The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
Calculate the moles of the gas using the gas law,
PV=nRT, where n is the moles and R is the gas constant. Then divide the given mass by the number of moles to get molar mass.
Given data:
P= 4.972 atm
V= 9.583 L
n=?
R= 
T=31.8 +273= 304.8 K
Putting value in the given equation:
=n
n= 
Moles = 1.905 moles
1.905 moles of Helium gas are in the tube. Hence, option A is correct.
Learn more about the ideal gas here:
brainly.com/question/27691721
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#6).
Every 1,000 mL makes 1 L
How many 1,000mL are there in 2,800 mL ?
That's division.
(2,800 mL) / (1,000 mL) = <em>2.8 L</em>
#7).
The 'perimeter' means the 'distance all the way around'.
You have to know that both sides of a rectangle are the same length,
and also the top and bottom are the same length.
So the perimeter of this rectangle is
(2 yd) + (4.5 yd) + (2.yd) + (4.5 yd) = 13 yd .
Oops. The problem wants to know the perimeter in feet.
So you have to know that each yard is the same as 3 feet.
In order to find the number of feet in 13 yards, you have to
take 3 feet 13 <em><u>times</u></em> .
(3 feet) times (13) = <em>39 feet .</em>
#8).
For this one, you have to know that every 36 inches makes 1 yard.
How many 36 inches are there in 48 inches ?
That's division.
(48 inches) / (36inches) = <em>1 and 1/2 yards</em> .
#9).
For this problem, you have to know how to handle a mixed number,
and you also have to know that there are 16 ounces in 1 pound.
Add up the fruit:
(3-1/2 pounds) + (4 pounds) + 2 pounds) = <em><u>9-1/2 pounds</u></em>
Now, remember that each pound is the same as 16 ounces. So if you
want to find the number of ounces in 9-1/2 pounds, you have to take
16 ounces 9-1/2 times .
(16 ounces) times (9-1/2) = <em>152 ounces</em>.
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#10).
This one is just adding up some numbers. But after you finish doing that, you have to know that 1,000 meters is called '1 kilometer' .
Add up the distances that Omar ran:
(1,000 meters) + (1,625 meters) + (1,500 meters) = <em><u>4,125 meters</u></em>
The problem wants to know how many kilometers this is, so you have to figure out how many '1,000 meters' fit into 4,125 meters.
That's division.
(4,125 meters) / (1,000 meters) = <em>4.125 kilometers</em>
Answer:
The number of electrons in the outermost shell of an atom determines its reactivity. Noble gases have low reactivity because they have full electron shells. Halogens are highly reactive because they readily gain an electron to fill their outermost shell.
Explanation:
I hope this helped!
