When muscles are moved this represents a transfer from chemical energy to mechanical energy. As always, energy is conserved in the system. Kinetic energy can then come from the mechanical energy.
Answer: C) 0.020 m
Explanation:
Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.
where,
n = moles of solute
= weight of solvent in g
Mole fraction of 
is = 
i.e. moles of is present in 1 mole of solution.
Moles of solute 
=
moles of solvent (water) = 1 - = 0.99
weight of solvent =
Molality =
Thus approximate molality of in this solution is 0.020 m
Answer:
B. It shows the ratio of elements in the compound.
Explanation:
Empirical formula tells about the ration of the elements found in the compound . The ratio are in complete number .
For example the molecular formula of glucose is C₆ H₁₂O₆
Its empirical formula = CH₂O
The balanced chemical reaction for this would be written as:
2Mg + O2 = 2MgO
We use this reaction and the amount of the reactant given to calculate for the amount of magnesium oxide that is produced. We do as follows:
1.5 g Mg (1 mol / 24.31 g) ( 2 mol MgO / 2 mol Mg ) (40.30 g /1 mol ) = 2.49 g MgO produced
