0.05 mol of oxygen atom.
Explanation:
Mass of potassium hydroxide = 2.79g
Unknown:
Number of moles = ?
Solution:
To solve this problem, find the number of moles of the potassium hydroxide.
Number of moles of KOH =
Molar mass of KOH = 39 + 16 + 1 = 56g/mol
Number of moles of KOH = = 0.05mole
Now,
1 mole of KOH contains 1 mole of oxygen atom
0.05 mole of KOH will have 0.05 mole of oxygen atom.
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Number of moles brainly.com/question/1841136
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-The products and reactants of both reactions are gases. -A catalyst is used for reaction 2. What do the symbols tell you about the conditions of the reaction shown to the right? ... They show that the number of atoms of each element is the same in the products and reactants.
Answer:evaporation from lakes and rivers
Explanation:I took the test
Answer:
The correct answer is 12.58 grams.
Explanation:
Based on the given information, the electrolysis equation will be,
Al³⁺ + 3e⁻ ⇔ Al
1 mol of Al needs 3 moles of electron, and the value for 1 mole of electron is 96485 C.
Thus, 1 mole of Al needs 3 × 96485 C = 289455 C
Now the amount of charge passed is,
T = 2.5 hours
= 2.5 × 3600 s = 9 × 10³ s
Q = Current × Time
= 15A × 9 × 10³ s
= 13.5 × 10⁴ C
The moles of Al plated will be,
= 13.5 × 10⁴ / 289455
= 0.4664 mol
The molecular mass of Al is 26.98 grams per mole
Now the mass of Al will be,
= Number of moles × Molecular mass
= 0.4664 × 26.98
= 12.58 grams
The rounded three digits for the given number is 2.46
<u>Explanation:</u>
Significant figures are the number of digits in a value which contributes to the degree of accuracy of the value while measuring
<u>Rules:</u>
- Digits which are not zero are always essential.
- Any zeros between two major digits are important.
- Only a final zero or trailing zeros are important in the decimal section
<u>Solution:</u>
- Given number- 2.45986
- Decimals- 5 digits
- Scientific Notation
-2.45986 × 10^0
- Applying the rules until rounding the 3 digits we get,
- The rounded three digits for the given number is 2.46
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