Answer:
-37.63KJ
Explanation:
First, we write an equation of reaction:
H + Br ——-> HBr
Now we are told that 155g of HBr is formed. We can calculate the number of moles of HBr formed as follows:
We simply divide the mass of the HBr formed by the molar mass of HBr. The molar mass of HBr is 81g/mol
The number of moles of HBr formed is thus 81/155 = 0.52 moles
The amount of heat released is thus 0.52 * (-72) = -37.63KJ
Animal cells have a centrosome and lysosomes, whereas plant cells do not.
Answer:
The percentage of the block contains 15% after 60 years.
Explanation:
Step 1: Formula for half-life time
To calculate the half-life time we will use the following formula:
At = A0 * 1/2 ^(x/t)
With At = the quantity after a time t
A0 = The quantity at time t = 0 (start)
x = time in this case = 60 years
t= half-life time = 22 years
Step 2: Calculate the percentage after 60 years
In this case: after 60 years the percentage will be
A0= 10 * 1/2 ^(60/22)
A0 = 1.5
A0 / At = 1.5 /10 = 0.15
0.15 *100% = 15 %
The percentage of the block contains 15% after 60 years.
Answer:
Answer is 2nd
Explanation:
some energy is transformed into mass
Answer:
the volume of gas inside this balloon = 146.3 L
Explanation:
Given that:
The temperature T = 31 °C = ( 31 + 273.15 )K = 304.15 K
The air pressure P = 0.700 atm
number of moles of gas n = 4.10 moles
Gas constant = 0.0821 L atm/K/mol
The objective is to calculate the volume of the gas inside the ballon.
Using the Ideal gas equation
PV = nRT
V = nRT/P
V = (4.10×0.0821×304.15)/0.700
V = 102.3799/0.700
V = 146.257 L
V = 146.3 L
Thus, the volume of gas inside this balloon = 146.3 L
