Why is it dangerous to react sodium and potassium with dulute sulphuric acid?
2 answers:
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We know that Molarity = # mol/L
In the question, we are given grams - so we need to calculate the number of moles that we are dealing with. We can do this by first finding out what the molecular formula of calcium hydroxide is:
This means that we have 1 calcium and 2 hydroxides.
We can find the number of moles by taking the grams given divided by the molar mass of the molecule. We can find the molar mass of the molecule by taking each atomic mass of each atom (found on the periodic table) and adding them together:
Ca = 40.08g
O = 15.999g
H = 1.008g
We have 1 calcium, 2 oxygens, and 2 hydrogens. So let's add the atomic masses together:
40.08 + 2(15.999) + 2(1.008) = 74.094g
Now that we have the molar mass, we can find the number of moles due to already knowing the given amount in the question:
54.21g/74.09g = 0.73 moles of
Now that we know the number of moles, we can solve for the molarity; The other part of the question gives us 560 mL of water - but this can quickly be converted to liters by moving the decimal to the left 3 places => 0.560 L
Knowing all of this information, we can plug it into the molarity equation:
Molarity = 0.73 mol/0.56 L
Molarity = 1.30
The molarity of the solution is 1.3 M.
In the question, we are given grams - so we need to calculate the number of moles that we are dealing with. We can do this by first finding out what the molecular formula of calcium hydroxide is:
This means that we have 1 calcium and 2 hydroxides.
We can find the number of moles by taking the grams given divided by the molar mass of the molecule. We can find the molar mass of the molecule by taking each atomic mass of each atom (found on the periodic table) and adding them together:
Ca = 40.08g
O = 15.999g
H = 1.008g
We have 1 calcium, 2 oxygens, and 2 hydrogens. So let's add the atomic masses together:
40.08 + 2(15.999) + 2(1.008) = 74.094g
Now that we have the molar mass, we can find the number of moles due to already knowing the given amount in the question:
54.21g/74.09g = 0.73 moles of
Now that we know the number of moles, we can solve for the molarity; The other part of the question gives us 560 mL of water - but this can quickly be converted to liters by moving the decimal to the left 3 places => 0.560 L
Knowing all of this information, we can plug it into the molarity equation:
Molarity = 0.73 mol/0.56 L
Molarity = 1.30
The molarity of the solution is 1.3 M.
Answer:
1) La masa del agua a temperatura ambiente es de 500 gramos, 2) La masa del agua cuando se congela es de 500 gramos, 3) La masa de agua que queda después de la evaporación es de 400 gramos, 4) Se ha evaporado 100 gramos de agua.
Explanation:
1) <em>¿Cuál es la masa de agua a temperatura ambiente?</em>
Podemos determinar la masa inicial del agua (), medido en gramos, al conocer su densidad (
), medida en gramos por mililitro, y volumen inicial ocupado en el vaso de precipitado (
), medido en mililitros, a partir de la siguiente expresión:
Si sabemos que y
, entonces:
La masa del agua a temperatura ambiente es de 500 gramos.
2) <em>¿Cuál es la masa de agua cuando se congela?</em>
Puesto que el proceso de congelación no implica transferencia de masa, la masa de agua se conserva al transformarse en hielo. Por tanto, la masa resultante es de 500 gramos.
3) <em>¿Cuál es la masa de agua que queda después de la evaporación?</em>
Durante la evaporación una parte del agua es transferida al aire, entonces podemos calcular la masa final (), medido en gramos, de la sustancia al multiplicar el volumen final (
), medido en mililitros, por la densidad del agua (
), medida en gramos por mililitro,. Es decir,
Si sabemos que y
, entonces:
La masa de agua que queda después de la evaporación es de 400 gramos.
4) <em>¿Qué masa de agua se evaporó? </em>
Determinamos que la masa evaporada de agua (), medida en gramos, es igual a la diferencia entre las masas inicial y final, ambas medidas en gramos:
Si y
, entonces tenemos que:
Se ha evaporado 100 gramos de agua.