<span>2.28 kg x 213 kJ/kg = 486 kJ = 4.86E+05 J</span>
Answer: :))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))
Explanation:
Answer:
b. 0.50 moles
Explanation:
To solve this problem we use <em>Avogadro's number</em> (6.023x10²³ atoms/mol).
By <u>dividing the number of atoms (or molecules) by that number</u>, we can calculate how many moles they represent.
- 3.01x10²³ atoms ÷ 6.023x10²³ atoms/mol = 0.50 moles
So the answer is option b. 0.50 moles.
Answer:
68.3%
Explanation:
First, let us look at the equation of reaction involving silver and magnesium chloride:
2Ag + MgCl2 ----> 2AgCl + Mg
1 mole of MgCl2 is required to precipitate 2 moles of Ag completely from the solution. That is a ratio of 1 to 2.
Now, mole of MgCl2 used to precipitate all the Ag
= molarity x volume
= 2.19 M x 2.89/1000
= 0.0063291 mole
Since 1 mole of MgCl2 would always require 2 moles of Ag, 0.0063291 mole will therefore require:
0.0063291 x 2 = 0.0126 mole of Ag
This means that 0.0126 mole of Ag is present in stephanie.
Mass of silver in stephanie = mole x molar mass
= 0.0126 x 107.8682
= 1.365 g
Thus, 1.365 g of silver is present in 2.00 g sample of stephanie.
Mass percent of silver in stephanie = 1.365/2.00 x 100
= 68.25% = 68.3% to the correct number of significant figure.