Help please!!!! I need to know the answer to this problem it would mean a lot if u helped :))

This question is about metal oxides. When sodium is heated in oxygen, sodium oxide is produced.

vodomira [7]

Answer:

This is very easy Cuz We have 2Na2O We have O2 so thats molecule of Oxygen and its same on product We need to balance Na on start We have 1 on product We have 2 so Just put 2 at start....

Explanation:

Sorry for bad english not my first language :(

2Na+O2-->2Na20

5 0

3 years ago

The British gold sovereign coin is an alloy of gold and copper having a total mass of 7.988 g, and is 22-karat gold.

azamat

Answer:

(a) $m_{gold}=7.322g$

(b)

$V_{gold}=0.379cm^3$

$V_{copper}=0.122cm^3$

(c) $\rho _{coin}=15.94g/cm^3$

Explanation:

Hello,

(a) In this case, with the given formula we easily compute the mass of gold contained in the sovereign as shown below:

$m_{gold}=\frac{m_{tota}*karats}{24}=\frac{7.988g*22}{24}=7.322g$

(b) Now, by knowing the density of gold and copper, 19.32 and 8.94 g/cm³ respectively, we compute each volume, by also knowing that the rest of the coin contains copper:

$V_{gold}=\frac{m_{gold}}{\rho_{gold}} =\frac{7.322g}{19.32g/cm^3}=0.379cm^3$