1 Answers
Call
It is a fact that if there is a mass of approximately 1.01 g of hydrogen atoms, there are Avogadro's number of hydrogen ATOMS. It is also a fact that Avogadro's number of copper atoms have a mass of 63.55 g. Both quantities represent a mole of stuff. This is a very important result to get your head around.
0
like
0 dislike
Talk Doctor Online in Bissoy App
The element copper has naturally occurring isotopes with mass numbers of 63 and 65. The relative abundance and atomic masses are 69.2% for a mass of 62.93 amu and 30.8% for a mass of 64.93 amu. What is the average atomic mass of copper?
$""^63Cu$ has $69.2%$ abundance. $""^65Cu$ has $30.8%$ abundance. So, the weighted average is $62.93xx69.2%$ $+$ $64.93xx30.8%$ $=$ $63.55$ $"amu"$. If we look at , copper metal (a mixture of isotopes...
1 Answers 1 views
2. The element copper has naturally occurring isotopes with mass numbers of 63 and 65. The relative abundance and atomic masses are 69.2% for a mass of 62.93 amu and 30.8% for a mass of 64.93 amu. How do you calculate the average atomic mass of copper?
And thus the $"weighted average"$ is: $(62.93xx69.2%+64.93xx30.8%)*"amu"$ $=$ $63.55$ $"amu"$
1 Answers 1 views
A sample of copper (Cu) contains 69.17% Cu-63. The remaining copper atoms are Cu-65. What is the average atomic mass of copper?
$"Average atomic mass"$ is the weighted average of the individual isotopes. And thus the weighted average $=$ $(0.6917xx63+0.3083xx65)*"amu"$ $=$ $"?? amu"$. Note that we have not accounted for the...
1 Answers 1 views
Pure copper may be produced by the reaction of copper(I) sulfide with oxygen gas as follows: $Cu_2S(s) + O_2(g) -> 2Cu(s) + SO_2(g)$. What mass of copper(I) sulfide is required in order to prepare 0.650 kg of copper metal?
You have given the stoichiometric equation that represents reduction of cuprous sulfide: $Cu_2S(s) + O_2(g) rarr 2Cu(s) + SO_2(g)$ Sulfur is oxidized; copper and oxygen are reduced. $"Moles of copper"=(650*g)/(63.55*g*mol^-1)=10.3*mol$....
1 Answers 1 views
A student investigated the reactions of copper carbonate and copper oxide with dilute hydrochloric acid. How can a sample of copper chloride crystals be made from copper carbonate and dilute hydrochloric acid?
$CuCO_3(s) + 2HCl(aq)rarrCuCl_2(aq) + CO_2(g)uarr + H_2O(l)$ Or........... $CuO(s) + 2HCl(aq)rarrCuCl_2(aq) + H_2O(l)$ For each acid base reaction the product is the beautiful blue-coloured $[Cu(OH_2)_6]^(2+)$ ion, which is commonly represented...
1 Answers 1 views
Copper is one of a group of metal called the coinage metals. How many atoms of copper are in a pure copper coin weighing 12.0 g?
$"Moles of copper"$ $=$ $(12.0*cancelg)/(63.55*cancelg*mol^-1)$ $=$ $0.189$ $mol$. Now in 1 mole of stuff there are $6.022xx10^23$ individual items of that stuff. is just a (large) number like a...
1 Answers 1 views
How many copper atoms are there in a mole of copper atoms? What is the number of copper atoms in $6.4*g$?
From your Periodic Table we learn that one mole of copper, $6.022xx10^23$ individual copper atoms have a mass of $63.55*g$. And thus we use the MASS of a chemical sample...
1 Answers 1 views
Hydrogen was passed over heated 2g copper oxide till only copper was left. The mass of copper obtained was was 1.6 grams. What is the percentage of oxygen in copper oxide?
There is a loss of 0.4 grams. $ 2.0 -1.6$ = 0.4 grams $ 0.4/2.0 xx 100 $ = 20% The Hydrogen will combine with the Oxygen in...
1 Answers 1 views
Copper will react with sulfur to form a copper sulfide, if 1.500g copper reacts with sulfur to form 1.880g of copper sulfide, what is the empirical formula of the copper sulfide?
The idea here is that you need to use the mass of copper and the mass of the copper sulfide to determine how much sulfur the produced compound contains, then...
1 Answers 1 views
An oxide of copper contains 2.118 g of copper and 0.2666 g of oxygen. Another oxide of copper contains the same mass of copper but 0.5332 g of copper. What are the empirical formulas of the oxides?
The empirical formulas are $"Cu"_2"O"$ and $"CuO"$. Oxide 1 $color(white)(mmmmml)"Cu" +color(white)(m) "O" → "Oxide 1"$ $"Mass/g":color(white)(l) 2.118color(white)(ll) 0.2666$ Our job is to calculate the ratio of the moles of...
1 Answers 1 views