Copper mass = 1.659
Copper moles = 1.659 / 64 = 0.0259
Sulfur mass = 2.08 - 1.659 = 0.421
Sulfur moles = 0.421 / 32 = 0.0131
Ratio Copper : Sulfur = 2 : 1
Empirical formula: Cu ₂ S
Name: Copper (I) sulfide
Basically stoichiometry is the measurement of elements, that is, the study of chemical quantities consumed or produced in a chemical reaction. When we are performing it we are using a special chemical counting unit: the mole, a unit of measurement, and one mole of a substance contains 6.022 * 10^23 particles. Now mole ratio is defined as the ratio of moles of one substance to the moles of another substance in a balanced equation. <span>If we are looking for the mole ratio between two substances, we need to look at the balanced equations</span> for the coefficients in front of the substances you are interested in.
This should be your guiding mantra for doing stoichiometry problems!
In his observation, he notices that the hydrogen atom only emitted light of a fixed wavelength. He was able to discover that the electrons only orbit the nucleus of the atom at discrete orbits. When the electron ‘jumps’ from a higher to lower level orbit, it emits a wavelength. These wavelengths are unique to atoms of an element and can be used to identify them hence he led the way to the establishment of the light spectrum.
Answer:- The right choice is A. 
.
Solution:- Latent heat of fusion means the heat required to melt the solid at constant temperature means there is no change in temperature only the solid changes to liquid. So, it is a solid to liquid phase change.
where q is the heat required to convert solid to liquid, m is the mass and 
is the latent heat of fusion.
From given info, 550 kJ that is 550000 J of heat is required to melt 14 kg of solid at 262K temperature. Let's rearrange the equation for latent heat of fusion and plug in the values in it.
= 
If we round this value to two sig figs and write in scientific notations then it becomes .
So, the right choice is A. .
Answer:
H3PO4 + 3NaOH ----> Na3PO4 + 3H2O
Explanation:
The balanced equation is given below
H3PO4 + 3NaOH ----> Na3PO4 + 3H2O
