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The given mass of cobalt chloride hydrate = 2.055 g
A sample of cobalt chloride hydrate was heated to drive off waters of hydration and the anhydrate was weighed.
The mass of anhydrous cobalt chloride = 1.121 g anhydrate.
The mass of water lost during heating = 2.055 g - 1.121 g = 0.934 g
Converting mass of water of hydration present in the hydrate to moles using molar mass:
Mass of water = 0.934 g
Molar mass of water = 18.0 g/mol
Moles of water = 
Answer:
Explanation:
Alka Seltzer tablet contains 325 mg of aspirin (acetylsalicylic acid), 1000 mg of citric acid, and 1916 mg of sodium bicarbonate. The acids originally contained in a tablet give only 17.4 mmol of H+, which is not enough to neutralize all of the sodium bicar- bonate (22.8 mmol).
Answer:

Explanation:
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In this case, according to the given STP (standard pressure and temperature), it is possible for us to realize that the equation to use here is the Avogadro's law as a directly proportional relationship between moles and volume:

In such a way, given the initial volume and both initial and final moles, we can easily compute the final volume as shown below:

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Answer:
moles
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass , occupies 22.4 L at STP and contains avogadro's number
of particles.
To calculate the moles, we use the equation:
Given mass of ethanol = 0.2301
Molar mass of ethanol = 46.07 g/mol
Thus there are
moles of ethanol are present in the sample.