Answer:

Explanation:
1. Calculate the mass of each element

2. Calculate the moles of each element

3. Calculate the molar ratios
Divide all moles by the smallest number of moles.

4. Round the ratios to the nearest integer
C:H = 1:2
5. Write the empirical formula
The empirical formula is 
3. volume of gas because its changing because of the temperature
4. 67.6 breaths per minute
65+73+67+71+62=338/5=67.6
^because there are five terms that we added
Answer:
Those with 3 protons and 3 neutrons are known as the isotope lithium-6. Those with 3 protons and 4 neutrons are known as the isotope lithium-7.
Explanation:
Answer: 20.775 g S
Explanation: 3.9x10^23 atoms = 0.648 mol
Atomic mass S = 32.08
S in grams = 20.775
Answer:
OPTION (A) : Testing a rock sample for gold content
Explanation:
For testing a rock sample of gold content you will need a Chemist. To test the material, the sample is rubbed on black stone which will leave a mark on the stone. This mark is tested by applying aqua fortis i.e nitric acid on the mark. If the mark gets dissolve then the material is not gold. If the mark sustain the it is further tested by applying aqua regia i.e nitric acid and hydrochloric acid which will prove the sample is of gold if it gets dissolve on using hydrochloric acid. The purity of the sample can be checked by differing the concentration of the aqua regia and comparing it with the gold material of the known purity.