The first law states that the total increase in the energy of a system is equal to the increase in thermal energy, meaning that heat is a form of energy and is therefore subject to the the principle of conservation
Answer:
The granite block transferred <u>4080 joules</u> of energy, and the mass of the water is <u>35.84 grams</u>.
Explanation:
The equation needed to answer both parts of the question is:
Q = mcΔT
In this equation,
-----> Q = energy/heat (J)
-----> m = mass (g)
-----> c = specific heat (J/g°C)
-----> ΔT = change in temperature (°C)
<u>Part #1:</u>
First, you need to find the energy transferred from granite block using the previous equation. You have been given the mass, specific heat, and change in temperature.
Q = ? J c = 0.795 J/g°C
m = 126.1 g ΔT = 92.6 °C - 51.9 °C = 40.7 °C
Q = mcΔT
Q = (126.1 g)(0.795 J/g°C)(40.7 )
Q = 4080
<u>Part #2:</u>
Secondly, using the energy calculated in Part #1, you need to calculate the mass of the water. You have calculated the energy transferred, and have been given the specific heat and change in temperature.
Q = 4080 J c = 4.186 J/g°C
m = ? g ΔT = 51.9 °C - 24.7 °C = 27.2 °C
Q = mcΔT
4080 J = m(4.186 J/g°C)(27.2 °C)
4080 J = m(113.8592)
35.84 = m
Answer: Bromine is the limiting reactant
Explanation:
First of all let's generate a balanced equation for the reaction
2Li + Br2 —> 2LiBr
Molar Mass of Li = 7g/mol
Molar Mass of Br2 = 2x80 = 160g/mol
From the question given, were told that 25g of Li and 25g Br2 were present at the take-off of the reaction. Converting these Masses to mole, we have:
Number of mole of Li = 25/7 = 3.6moles
Number of mole of Br2 = 25/160 = 0.156mol.
To know which is the limiting reactant, we have to compare the ratio of the number of mole of experimental Li and Br2 to that of theoretical Li and Br2
For the experimental yield:
Li : Br2 = 3.6/ 0.156 = 23 : 1
For the theoretical yield:
Li : Br = 2 : 1
From the above, we see clear that Br2 is the limiting reactant because according to the equation( which gives the theoretical yield), for every 2moles of Li, 1mole of Br2 is used up. But this is not so from the experiment conducted as 23moles required 1mole of Br2.
Answer:
a) That of Al is higher than that of Mg because Mg wants to lose the second electron, so it is easier to take the second electron away
