Number of second in human lives in scientific notation is 3.9 × 10⁷ second
<u>Given that;</u>
Average human lives = 74 years
<u>Find:</u>
Number of second in human lives in scientific notation
<u>Computation:</u>
Number of second in human lives in scientific notation = 74 × 365 × 24 × 60
Number of second in human lives in scientific notation = 38,894,400
Number of second in human lives in scientific notation = 3.9 × 10⁷ second
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Answer:
1.31x10⁻³ moles of H₂
Explanation:
This is the equation:
Mg(s) + 2H₂O (g) → Mg(OH)₂ (aq) + H₂(g)
Ratio is 1:1, so 1 mol of Mg is needed to produce 1 mol of H₂
Mass / Molar mass = Mol
0.032 g / 24.3 g/m = 1.31x10⁻³ moles
1.31x10⁻³ moles of H₂(g)
Basically this is used in calculating the nuclear binding energy by converting the mass defect (calculated first) to energy and if we recall, Einstein's equation E=mc2 is the perfection equation to use because E=mc2 in which E represents units of energy, m represents units of mass, and c 2 is the speed of light squared.
Answer:
b) 2.0 mol
Explanation:
Given data:
Number of moles of Ca needed = ?
Number of moles of water present = 4.0 mol
Solution:
Chemical equation:
Ca + 2H₂O → Ca(OH)₂ + H₂
now we will compare the moles of Ca and H₂O .
H₂O : Ca
2 : 1
4.0 : 1/2×4.0 = 2.0 mol
Thus, 2 moles of Ca are needed.
