And a water molecule, this is called a dehydration synthesis. when 2 molecule combine, a water molecule leave.
Answer:
Explanation:
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In this case, since this is a system in which the water is heated up and the metal is cooled down in a calorimeter which is not affected by the heat lose-gain process, we can infer that the heat lost by the metal is gained be water, it means that we can write:
Thus, in terms of masses, specific heats and temperatures we can write:
Whereas the equilibrium temperature is the given final temperature of 28.4 °C and we can compute the specific heat of the metal as shown below:
Plugging the values in and since the density of water is 1.00 g/mL so the mass is 80.0g, we obtain:
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The answer is A because it does
Let's assume we have 100 grams of this solution, and therefore 20.0 grams of NaOH, and 80.0 grams of water.
NaOH has a molar mass of 40.00 grams/mole, so we can convert NaOH to moles: (20.0 grams of NaOH) * (1 mole NaOH/40.00 grams NaOH) = 0.500 moles NaOH.
Next, we have a molar mass of water of 18.02 g/mol, so we can convert water to moles:
80.0 grams H2O * (1 mole H2O/18.02 grams) = 4.44 moles H2O
The mole fraction of NaOH is the moles of NaOH over the total moles of all parts of the solution. Therefore:
(0.500 moles NaOH)/(0.500 moles + 4.44 moles) = 0.101
0.101 = mole fraction of solute
The molal concentration is defined as the number of moles of solute over the number of kilograms of solvent (water).
We have 0.500 moles of NaOH, and 0.0800 kg of water, so it becomes:
(0.500 moles NaOH)/(0.0800 kg H2O solvent) = 6.25 molal solution
