Answer:
(A) 15.0 °C
Explanation:
The water in beaker A gains heat because its initial temperature (10 °C) is less than the initial temperature of the water in beaker B (20 °C) which loses heat.
Let T3 be the final temperature
Heat gained by beaker A = heat loss by beaker B
mc(T3 - T1) = mc(T2 - T3)
The mass and specific heat of water in both beakers are the same. Therefore, (T3 - T1) = (T2 - T3)
T1 is initial temperature of beaker A = 10 °C
T2 is initial temperature of beaker B = 20 °C
T3 - 10 = 20 - T3
T3 + T3 = 20 + 10
2T3 = 30
T3 = 30/2 = 15 °C
<h3>
Answer:</h3>
28.52 seconds
<h3>
Explanation:</h3>
Initial number of atoms of Nitrogen 12,000 atoms
Half-life = 7.13
Number of atoms after decay = 750 atoms
We are required to determine the time taken for the decay.
Note that half life is the time taken for a radioactive isotope to decay to a half of its original amount.
Using the formula;
Remaining amount = Initial amount × (1/2)^n , where n is the number of half lives
In our case;
750 atoms = 12,000 atoms × (1/2)^n
0.0625 = 0.5^n
n = log 0.0625 ÷ log 0.5
n = 4
But, 1 half life =7.13 seconds
Therefore;
Time taken = 7.13 seconds × 4
= 28.52 seconds
Therefore, the time taken for 12,000 atoms of nitrogen to decay to 750 atoms is 28.52 seconds
134.5 grams in 4.5 moles of Li2O (lithium oxide).
To get the empirical formula of this compound, we take a basis of 100 grams which means each percentage is equivalent to 1 gram. Hence there is 32.39 grams sodium, 22. 53 grams sulfur and 45.07 grams oxygen. We convert each mass to their moles by dividing by their respective molar mass. Na: 1.408, S:0.704 and O:2.82. divide each with the lowest: Na: 2: S: 1 and O:4. Hence the formula is Na2SO4.
<h3><u>Answer;</u></h3>
10.80 ° C
<h3><u>Explanation;</u></h3>
From the information given;
Initial temperature of water = 24.85°C
Final temperature of water = 35.65°C
Mass of water = 1000 g
The specific heat of water ,c = 4.184 J/g °C.
The heat capacity of the calorimeter = 695 J/ °C
Change in temperature ΔT = 35.65°C - 24.85°C
= 10.80°C
