Question: Given the balanced equation representing a reaction:
2H2 + O2 ==>2H2O
What is the total mass of water formed when 8 grams of hydrogen reacts completely with 64 grams of oxygen?
(1) 18 g (3) 56 g
(2) 36 g (4) 72 g
Answer:
"72 gram" is the total mass of water formed when 8 grams of hydrogen reacts completely with 64 grams of oxygen
Explanation:
We will do stoichiometry in this kind of problem:
Therefore, the total mass of water formed is 72 g.
Answer:
Option A
Explanation:
Addition of too much of solvent will make the solution dilute due to which the crystals will not form. Hence option D is incorrect
On the other hand adding a minimum amount of boiling solvent will give a saturated solution for recrystallization. Hence, option A is incorrect
Addition of cold solvent will lower the rate of formation of crystals. Hence, both option B and C are incorrect
Answer:
The Kinetic Energy is approximately 3 times decreased
Explanation:
A baseball weighs 5.13 oz.
a)What is the kinetic energy, in joules, of this baseball when it is thrown by a major league pitcher at 95.o mi/h?
b) By what factor will the kinetic energy change if the speed of the baseball is decreased to 54.8 mi/h? Express your answer as an integer.
Kinetic Energy (KE)=0.5×mass×velocity ^ 2
Kinetic Energy (KE)=0.5×mass × velocity ^ 2
Joules = kg×m^2/s^2
1 mile = 1609.344 meters
1 hour = 3600 sec
1 Oz = 28.34952 g = 0.02834952 kg
a) KE=0.5×m×v^2
=0.5×(5.13 oz × 0.02834952 kg/1 ounce)×(95 miles/h × 1609.344 m/1 mile × 1 hr/3600 s)^2
=130.761 kg×m^2/s^2 = 130.761 Joules
b) KE=0.5×m×v^2
=0.5×(5.13 oz × 0.02834952 kg/1 ounce)×(54.8 miles/h × 1609.344 m/1 mile × 1 hr/3600 s)^2
=43.51028 kg×m^2/s^2 = 43.51028 Joules
= 130.761 / 43.51028 = 3.00528,
As such the Kinetic Energy is approximately 3 times decreased
Answer : The pH of the solution is, 9.18
Solution : Given,
Concentration (c) = 0.025 M
Base dissociation constant =
The equilibrium reaction for dissociation of (weak base) is,
initially conc. c 0 0
At eqm.
First we have to calculate the concentration of value of dissociation constant .
Formula used :
Now put all the given values in this formula ,we get the value of dissociation constant .
By solving the terms, we get
Now we have to calculate the concentration of hydroxide ion.
Now we have to calculate the pOH.
Now we have to calculate the pH.
Therefore, the pH of the solution is, 9.18
Draw conclusions,............