Note that
The heating value of standard coal is about 30,080 kJ/kg
1 L of water has a mass of 1.0 kg
The mass of 15 L of water = 15 kg.
The latent heat of vaporization of water is about 2260 kJ/kg,
The energy required to boil 15 L of water is
(2260 kJ/kg)*(15 kg) = 33900 kJ
The mass of coal required to provide this energy is
(33900 kJ)/(30080 kJ/kg) = 1.127 kg
Because 1 kg = 2.205 lb, the mass of coal required is
(1.127 kg)*(2.205 lb/kg) = 2.485 lb
Answer: 2.49 lb (nearest hundredth)
Answer:
Explanation:
Hello!
In this case, when performing mathematical operations with numbers in scientific notation, the first step is to write them in standard notation:
550 - 65.0
Thus, the result without any significant figures-based analysis is:
615.0
However, since 550 is significant to the ones and 65.0 to the tenths, we need to round the result to the bigger significance, in this case to the ones; therefore the appropriate result would be:
615
That in scientific notation would be:
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Answer:</h3>
43.27 g Mg
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Explanation:</h3>
The balanced equation for the reaction between magnesium metal and hydrochloric acid is;
Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g)
From the equation;
1 mole of magnesium reacts with 2 moles of HCl
We are given;
3.56 moles of Mg and 3.56 moles of HCl
Using the mole ratio;
3.56 moles of Mg would react with 7.12 moles of HCl, and
3.56 moles of HCl would react with 1.78 moles of Mg
Therefore;
The amount of magnesium was in excess;
Moles of Mg left = 3.56 moles - 1.78 moles
= 1.78 moles
But; 1 mole of Mg = 24.305 g/mol
Therefore;
Mass of magnesium left = 1.78 moles × 24.305 g/mol
= 43.2629 g
= 43.27 g
Thus, the mass of magnesium that remained after the reaction is 43.27 g
Temperature. In case you have ever baked, you can relate to this. For example, when you make caramel, you simply put the caramel on a boiling hot pan and sit back and watch it. It always goes fastest this way.
Im sorry but its a pdf i can write on it :(
