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 : The balanced chemical equation is,

Explanation :
Rules for the balanced chemical equation in basic solution are :
- First we have to write into the two half-reactions.
- Now balance the main atoms in the reaction.
- Now balance the hydrogen and oxygen atoms on both the sides of the reaction.
- If the oxygen atoms are not balanced on both the sides then adding water molecules at that side where the more number of oxygen are present.
- If the hydrogen atoms are not balanced on both the sides then adding hydroxide ion
at that side where the less number of hydrogen are present. - Now balance the charge.
The half reactions in the basic solution are :
Reduction :
......(1)
Oxidation :
.......(2)
Now multiply the equation (1) by 2 and then added both equation, we get the balanced redox reaction.
The balanced chemical equation in a basic solution will be,

This question includes four answer choices:
A. definite volume, highest molecular motion, highest kinetic energy
B. indefinite volume, least molecular motion, highest kinetic energy
C. definite volume, least molecular motion, lowest kinetic energy
D. definite volume, no molecular motion, lowest kinetic energy
Solids do not have the highest molecular motion (on the contrary they have the least molecular motion), so you can discard option A. Solids have a definite volume and the highest kinetic energy (given that they have the least molecular motion), so you discard option C. Molecules always have a vibrational motion, so you discard option D. Option C, have only characteristics that correctly describes a solid: definite volume, least molecular motion, lowest kinetic energy. Therefore, the answer is the option C.
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Answer:
Mass of KCL = 218 grams.
Explanation:
Step 1: calculate the heat that must be absorbed(q).
Heat that must be absorbed(q) is calculated as follows:
q= m c (T2-T1).
q = 750g (4.18 J/gC)(20-4 C) = 5.016X10^4 J = 50.16 kJ
Step 2: we determine moles of KCL as follows:
Moles KCl = 50.16 kJ / 17.2 kJ/mol = 2.92 moles.
Step 3: calculate mass of KCL:
Mass of KCl = 2.92 mol X 74.55 g/mol = 218g.
Therefore, 218 grams of KCL would have to be dissolved into 750 g of 20.0°C H2O to produce the solution.