Answer : The heat your body transfer must be, 25.1 kJ
Explanation :
Formula used :
or,
where,
Q = heat = ?
m = mass of water = 500.0 g
c = specific heat of water = 
= initial temperature = 
= final temperature = 
Now put all the given value in the above formula, we get:
Therefore, the heat your body transfer must be, 25.1 kJ
Answer:
C = 18.29 g
Explanation:
Given data:
Mass of beryllium needed = ?
Mass of nitrogen = 18.9 g
Solution:
Chemical equation:
3Be + N₂ → Be₃N₂
now we will calculate the number of moles of nitrogen:
Number of moles = mass/molar mass
Number of moles = 18.9 g/ 28 g/mol
Number of moles = 0.675 mol
Now we will compare the moles of nitrogen and Be from balance chemical equation.
N₂ : Be
1 : 3
0.675 : 3/1×0.675 = 2.03 mol
Number of moles of Be needed are 2.03 mol.
Mass of Beryllium:
Mass = number of moles × molar mass
Mass = 2.03 mol × 9.01 g/mol
Mass = 18.29 g
80 protons,121 Neutrons, and 80 electrons the element is Mercury
Answer:
-26.125 kj
Explanation:
Given data:
Mass of water = 250.0 g
Initial temperature = 30.0°C
Final temperature = 5.0°C
Amount of energy lost = ?
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = T2 - T1
ΔT = 5.0°C - 30.0°C
ΔT = -25°C
Specific heat of water is 4.18 j/g.°C
Now we will put the values in formula.
Q = m.c. ΔT
Q = 250.0 g × 4.18 j/g.°C × -25°C
Q = -26125 j
J to kJ
-26125 j ×1 kj /1000 j
-26.125 kj
<h3>
Answer:</h3>
81.9 grams
<h3>
Explanation:</h3>
From the question we are given;
- Half-life of C-14 is 5730 years
- Original mass of C-14 (N₀) = 150 grams
- Time taken, t = 5000 years
We are required to determine the mass left after 5000 years
- N = No(1/2)^t/T, where N is the remaining mass, N₀ is the original mass, t is the time taken and T is the half-life.
t/T = 5000 yrs ÷ 5730 yrs
= 0.873
N = 150 g ÷ 0.5^0.873
= 150 g × 0.546
= 81.9 g
Therefore, the mass of C-14 left after 5000 yrs is 81.9 g
