Answer:
structure of argon
Explanation:
The nucleus contains 18 protons ( red) and 22 neutrons (orange). 18 electrons (white) occupy shells ring.
Answer:
It will take 28.5 minutes
Explanation:
<u>Step 1: </u>Data given
Mass of Cu = 4.50 grams
8.00 A of current are used
Molar mass of Cu = 63.5 g/mol
Step 2: Calculate time needed
Cu2+ →Electricity → Cu
we notice a flow of 2 electrons ⇒ This means the Faraday constant = 2F
Since Molar mass of Cu is 63.5 g/mol
63.5 grams of Cu is deposited by 2*96500 C
4.50 grams of Cu ((2*96500)/63.5) * 4.50 = 13677.17 C
Q = It
13677.17 = 8t*60 seconds
t = 28.5 minutes
Answer:
Dissolving sugar in water, burning paper, and melting gold are all chemical changes
Explanation:
The action cannot be reversed, or undone. Therefore it is a chemical change.
Boiling water is a physical change.
From the given pH, we calculate the concentration of H+:
[H+] = 10^-pH = 10^-5.5
We then use the volume to solve for the number of moles of H+:
moles H+ = 10^-5.5M * 4.3x10^9 L = 13598 moles
From the balanced equation of the neutralization of hydrogen ion by limestone written as
CaCO3(s) + 2H+(aq) → Ca2+(aq) + H2CO3(aq)
we use the mole ratio of limestone CaCO3 and H+ from their coefficients, which is 1 mole of CaCO3 is to react with 2 moles of H+, to compute for the mass of the limestone:
mass CaCO3 = 13598mol H+(1mol CaCO3/2mol H+)
(100.0869g CaCO3/1mol CaCO3)(1kg/1000g)
= 680 kg
