All organisms need four types of organic molecules: nucleic acids, proteins, carbohydrates and lipids; life cannot exist if any of these molecules are missing.
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The kind of thermochemical equation represented below
that is
CaO(s) + H2O (l) = Ca(OH)2 (s) +65.2 kj
is exothermic ( answer B)
This is because its heat energy has a + sign meaning that heat is released by the reaction above.
Answer:
B. They are dimensionless ratios of the actual concentration or pressure divided by standard state concentration, which is 1 M for solutions and 1 bar for gases.
Explanation:
Activity of a substance is defined as the ratio of an effective concentration or an effective pressure to a standard state pressure or a standard state pressure. It is usually a unit less ratio.
Concentrations in an equilibrium constant are really dimensionless ratios of actual concentrations divided by standard state concentrations. Since standard states are 1 M for solutes, 1 bar for gases, and pure substances for solids and liquids, these are the units to be used.
Hence, activity is a fudge factor to ideal solutions that correct the true concentration. Activity of a gas and solute concentration is a ratio with no unit.
If 5.0 grams of KCl is dissolved in 500 ml of water, the concentration of the resulting solution will be 0.134M.
<h3>How to calculate concentration?</h3>
The concentration of a solution can be calculated by using the following formula;
Molarity = no of moles ÷ volume
According to this question, 5.0 grams of KCl is dissolved in 500 ml of water. The concentration is calculated as follows:
no of moles of KCl = 5g ÷ 74.5g/mol = 0.067mol
Molarity = 0.067mol ÷ 0.5L = 0.134M
Therefore, if 5.0 grams of KCl is dissolved in 500 ml of water, the concentration of the resulting solution will be 0.134M.
Learn more about concentration at: brainly.com/question/10725862
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