Answer:
46.96 amu
Explanation:
Isotopes are different kinds of same elements. The difference between two isotopes of the same element is the number of neutrons.
To get the relative atomic mass, we take into consideration the masses of the different isotopes. This is done by multiplying their abundances by their masses. They are then added together to get the relative atomic mass of the element.
Let the isotopic mass of 47Z be x
45.36 = [80/100 * 44.96] + [20/100 * x]
45.36 = 35.968 + 0.2x
0.2x = 45.36 - 35.968
0.2x = 9.392
x =9.392/0.2 = 46.96 amu
A attract a core pair of electrons toward itself
Answer:
20.95 g of caffeine, C₈H₁₀N₄O₂
Explanation:
From the question given above, the following data were obtained:
Number of molecules of C₈H₁₀N₄O₂ = 6.5×10²² molecules
Mass of C₈H₁₀N₄O₂ =?
From Avogadro's hypothesis,
1 mole of C₈H₁₀N₄O₂ = 6.02×10²³ molecules
Next, we shall determine the mass of 1 mole of C₈H₁₀N₄O₂. This can be obtained as follow:
1 mole of C₈H₁₀N₄O₂ = (8×12) + (10×1) + (4×14) + (2×16)
= 96 + 10 + 56 + 32
1 mole of C₈H₁₀N₄O₂ = 194 g
Thus,
194 g of C₈H₁₀N₄O₂ = 6.02×10²³ molecules
Finally, we shall determine the mass of caffeine, C₈H₁₀N₄O₂ that contains 6.5×10²² molecules. This can be obtained as follow:
6.02×10²³ molecules = 194 g of C₈H₁₀N₄O₂
Therefore,
6.5×10²² molecules = (6.5×10²² × 194) / 6.02×10²³
6.5×10²² molecules = 20.95 g of C₈H₁₀N₄O₂.
Therefore, 20.95 g of caffeine, C₈H₁₀N₄O₂ contains 6.5×10²² molecules
Answer:
92.8%
Explanation:
Step 1: Given data
- Mass of lead in the bullet (mPb): 11.6 g
- Mass of tin in the bullet (mSn): 0.5 g
- Mass of antimony in the bullet (mSb): 0.4 g
Step 2: Calculate the total mass of the bullet
The total mass of the bullet is equal to the sum of the masses of the elements that form it.
m = mPb + mSn + mSb = 11.6 g + 0.5 g + 0.4 g = 12.5 g
Step 3: Calculate the mass percentage of Pb in the bullet
We will use the following expression.
%Pb = mPb / m × 100%
%Pb = 11.6 g / 12.5 g × 100% = 92.8%
