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2 years ago

An element's atomic number is 65. How many protons would an atom of this element have?

Chemistry

1 answer:

KIM [24]2 years ago

7 0

65. The atomic number is the number of protons in the atom.

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Magnesium (average atomic mass = 24.3050 amu) consists of three isotopes with masses 23.9850 amu, 24.9858 amu, and 25.9826 amu.

iris [78.8K]

Answer: The first isotope has a relative abundance of 79% and last isotope has a relative abundance of 11%

Explanation: Given that the average atomic mass(M) of magnesium

= 24.3050amu

Mass of first isotope (M1) = 23.9850amu

Mass of middle isotope (M2)=24.9858amu

Mass of last isotope(M3)= 25.9826amu

Total abundance = 1

Abundance of middle isotope = 0.10

Let abundance of first and last isotope be x and y respectively.

x+0.10+y =1

x = 0.90-y

M = M1 × % abundance of first isotope + M2 × % of middle isotope +M3 ×% of last isotope

24.03050= 23.985× x + 24.9858 ×0.10 + 25.9826×y

Substitute x= 0.90-y

Then

y = 0.11

Since y=0.11, then

x= 0.90-0.11

x=0.79

Therefore the relative abundance of the first isotope = 11% and the relative abundance of the last isotope = 79%

5 0

2 years ago

Rocks beneath the surface are forced toward the________.

Angelina_Jolie [31]

Ans

the mantle

Explanation:

7 0

2 years ago

Read 2 more answers

Researchers are investigating processed that happen during digestion which answer choice describes only a physical change during

dolphi86 [110]

Answer:Chewing in the mouth breaks food into smaller pieces

Explanation: all you are doing is breaking down the food in your mouth

6 0

2 years ago

Save the ________ used to extract metals.

MrRa [10]

Answer:

Save the *minerals* used to extract metals.

6 0

2 years ago

If 842 grams of sodium hydroxide reacts with 750.0 grams of aluminum, how many grams of aluminum hydroxide should theoretically

Phantasy [73]

548.55 grams of aluminum hydroxide should theoretically form.

Explanation:

Balanced equation for the reaction:

3 NaOH + Al ⇒ Al(OH)3 +3 Na

DATA GIVEN:

mass of NaOH = 842 grams, atomic mass =39.9 grams/mole

mass of Al = 750 grams, atomic mass = 26.9 grams/mole

aluminum hydroxide theoretical yield = ?

Moles of NaOH reacted

number of moles = $\frac{mass}{atomic mass of 1 mole}$

putting the values in the equation

NaOH = $\frac{842}{39.9}$

= 21.1 MOLES OF NaOH

Al = $\frac{750}{26.9}$

= 27.8 moles

from the equation

from 3 moles of NaOH 1 mole of Al(OH)3 is produced

21.1 moles of NaOH will react to give x moles of Al(OH)3

$\frac{1}{3}$ = $\frac{x}{21.1}$

7.03 moles of Al(OH)3 is formed.

and

1 mole of Al(OH)3 is formed from 1 mole of Al in the reaction

so, 27.8 Moles will react to give give 27.8 moles of Al(OH)3 limiting reagent of the given reaction is NaOH

mass of Al(OH)3 =7.03 x 78 (atomic mass of Al(OH)3)

= 548.55 grams

theoretical yield from the given data is 548.55 grams

3 0

2 years ago