Given :
Mass of gold ( Au ) is 212 gram.
To Find :
Atoms of gold present in 212 gram of gold.
Solution :
Molecular mass of gold is 197 gram.
So, number of moles of gold in 212 gram is :
Now, we know 1 mole of any element contains 
atoms.
So, number of atoms present in 1.076 moles are :
Hence, this is the required solution.
4)<span>1.24⋅<span>1024</span></span><span> formula units
</span>1 mole Na<span> (sodium)</span>
Answer:
B. Lower
Explanation:
Remember that the pH is calculated as
-log (H30 +)
That is, at a higher concentration of H30 +, with the -log, the pH value decreases and vice versa.
With a concentration 1e-5, it yields a pH of 5.00 and with 1e-2 a value of 2.00
Copper oxidizes in moist air
2Cu + CO₂ + O₂ + H₂O = (CuOH)₂CO₃
copper reacts with concentrated acids, for example, with nitric acid
Cu + 4HNO₃ = Cu(NO₃)₂ + 2NO₂ + 2H₂O
copper reacts with chlorine
Cu + Cl₂ = CuCl₂
copper reacts with oxygen when heated
2Cu + O₂ = 2CuO
Answer:
The solution would need 13.9 g of KCl
Explanation:
0.75 m, means molal concentration
0.75 moles in 1 kg of solvent.
Let's think as an aqueous solution.
250 mL = 250 g, cause water density (1g/mL)
1000 g have 0.75 moles of solute
250 g will have (0.75 . 250)/1000 = 0.1875 moles of KCl
Let's convert that moles in mass (mol . molar mass)
0.1875 m . 74.55 g/m = 13.9 g
