Answer: 1.79 x 10^-5
Explanation: The equilibrium constant of a reaction can be calculated from the quotient of the concentrations of the products over the concentrations of the reactants, with each termed raised to their respective stoichometric coefficients.
For acetic acid, this equilibrium expression is:
![Kc=\frac{[H+] [CH3COO-]}{[CH3COOH]}](https://tex.z-dn.net/?f=Kc%3D%5Cfrac%7B%5BH%2B%5D%20%5BCH3COO-%5D%7D%7B%5BCH3COOH%5D%7D)
Replacing the equilibrium concentrations given by the exercise into the expression above, the equilibrium constant, Kc will be obtained and it is found to be equal to 1.79 x 10^-5.
Answer: The final velocity of both man and hokey puck will be 0.056 m/s.
Explanation: We are given 2 objects and are undergoing collision. The final velocity of both the objects is same. To calculate the final velocity, we will use the principle of conservation of momentum.
This principle states that when the objects that are colliding makes up a system, then the total momentum will remain constant if no external force is applied on it.
Sum of Initial momentum of two objects = Sum of Final momentum of the two objects
Mathematically,
...(1)
where,
are the mass, initial velocity and final velocity of the first object.
are the mass, initial velocity and final velocity of the second object.
Here, man and hockey puck are moving together after the collision, so their final velocities will be same.

Putting values in equation 1, we get:


The final velocity of man and hockey puck is 0.056 m/s.
B , Biosphere is a special shell of the Earth inhabited by living organisms
Answer:
1.57×10²³ molecules
Explanation:
Given data:
Number of molecules of ethanol = ?
Volume of ethanol = 15.0 mL
Density of ethanol = 0.789 g/mL
Solution:
Mass of ethanol :
Density = mass/ volume
0.789 g/mL = mass/ 15.0 mL
Mass = 0.789 g/mL× 15.0 mL
Mass = 11.84 g
Number of moles of ethanol:
Number of moles = mass/molar mass
Number of moles = 11.84 g / 46.07 g/mol
Number of moles = 0.26 mol
1 mole contain 6.022×10²³ molecules
0.26 mol × 6.022×10²³ molecules / 1mol
1.57×10²³ molecules
Environmental selective pressures. In other words, natural selection took place. It was the environment that caused these changes. Birds on the islands with the most suitable traits for survival thrived while the birds that didn't die.