You could ask whether the black crust is a new substance formed from silver underwent a chemical change because a chemical change produces a new substance.
Answer:
You have to prepare for the lab (Materials, work, paper etc.)
Set up the lab know where the lab will be taking place
Read thru the experiment before doing the lab
Make a hypothesis
Write down notes, observations, measures anything important to help with the lab!
Answer:
its atomic number will be 3 and it's mass number will be 7. it is lithium
Answer:
Mole fraction H₂O → 0.72
Mole fraction C₂H₅OH → 0.28
Explanation:
By the mass of the two elements in the solution, we determine the moles of each:
25 g . 1 mol/ 18g = 1.39 moles of water (solute)
25 g . 1 mol / 46 g = 0.543 moles of ethanol (solvent)
Mole fraction solute = Moles of solute / Total moles
Mole fraction solvent = Moles of solvent / Total moles
Total moles = Moles of solute + Moles of solvent
1.39 moles of solute + 0.543 moles of solvent = 1.933 moles → Total moles
Mole fraction H₂O = 1.39 / 1.933 → 0.72
Mole fraction C₂H₅OH= 0.543 / 1.933 → 0.28
Remember that sum of mole fractions = 1
While terrestrial biomes are shaped by air temperature and precipitation, aquatic systems are characterized by factors such as water salinity, depth, and whether the water is moving or standing. If that's what you mean?
