Answer:
20.4 grams Zn
Explanation:
To find the mass, you first need to find the moles. This can be found using the Ideal Gas Law equation:
PV = nRT
In this equation,
-----> P = pressure (atm)
-----> V = volume (L)
-----> n = moles
-----> R = Ideal Gas Constant (0.08206 atm*L/mol*K)
-----> T = temperature (K)
Before you can plug the values into the equation, you need to convert Celsius to Kelvin.
P = 0.980 atm R = 0.08206 atm*L/mol*K
V = 7.80 L T = 25.0 °C + 273.15 = 298.15 K
n = ? moles
PV = nRT
(0.980 atm)(7.80 L) = n(0.08206 atm*L/mol*K)(298.15 K)
7.644 = n(24.466)
0.312 moles = n
Now that you have the number of moles, you can convert it to grams using the atomic mass of zinc. The final answer should have 3 sig figs to match the sig figs in the given values.
Atomic Mass (Zn): 65.380 g/mol
0.312 moles Zn 65.380 grams
------------------------- x ------------------------- = 20.4 grams Zn
1 mole
Answer:
11.7
Explanation:
The pH is the negative logarithm of the concentration of H+ ions. If the concentration is 2×10-¹² the the pH will be -log(2×10-¹²) which is 11.698 which can be round up to 11.7.
Answer: The final temperature will be 
Explanation:
To calculate the specific heat of substance during the reaction.

where,
q = heat absorbed =41840 J
c = specific heat = 
m = mass of water = 200 g
= final temperature =?
= initial temperature = 
Now put all the given values in the above formula, we get:


Thus the final temperature will be 
HA ⇄ H⁺ + A⁻
so:
![\frac{[H^+][A^-]}{[HA]} = 1.5 x 10^{-5}](https://tex.z-dn.net/?f=%20%5Cfrac%7B%5BH%5E%2B%5D%5BA%5E-%5D%7D%7B%5BHA%5D%7D%20%3D%201.5%20x%2010%5E%7B-5%7D%20%20)
and now:

= 1.5 x 10⁻⁵
x is considered very small compared to 0.15
x² = 2.25 x 10⁻⁶
x = 1.5 x 10⁻³
So [H⁺] = 1.5 x 10⁻³
pH = - log [H⁺] = - log (1.5 x 10⁻³) = 2.83