102 grams.
Equation:
Quantify of heat = mass x specific heat x difference in temperature
We have: quantity of heat : 2300J
specific heat: .449 J/g
difference in t: 80 - 30 = 50
Solve for mass: 2300 = mass x 0.449 x 50
mass = 102.449
2 sig-figs --> 102 grams
Molarity
Molarity is a unit used to express the concentration of a substance, and it is defined as the number of moles of solute per decimeter cubed (liter) of solvent.
Answer:
Explanation:
If percentage are given then we are taking total mass is 100 grams.So, the mass of each element is equal to the percentage given.
Mass of Mg = 10.89 g
Mass of Cl = 31.77 g
Mass of O = 57.34 g
Step 1 : convert given masses into moles.
Moles of Mg=
Moles of Cl = 
Moles of O =
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For Mg = 
For Cl = 
For O= 
The ratio of Mg :Cl : O= 1 : 2 : 8
Hence the empirical formula is