The answer should be the first one, cells are made of living things. Which is false, because living things do not make up cells, cells make up living things.
Answer:
The correct answer is making observations in his experiment. In his cathode ray tube experiment J. J. Thomson proved that the cathode rays are indeed negatively charged particles.
Answer:
2.71*10^24 formula units in 4.5 moles NaCl
Explanation:
Remark
Make sure you know what a formula unit it. In this case, what it consists of is 1 ion of Na+ Combined with 1 ion of Cl- Together they combine to make NaCl which is ordinary table salt.
1 mole contains 6.02 * 10 ^23 formula units of any chemical -- in this case NaCl.
Therefore 4.50 moles have 4.5 * 6.02*10^23 formula units.
Answer:2.71*10^24
Answer:
A. 85.6 g
= 0.0856 kg.
B. 0.00027 mol/g
= 0.27 mol/kg.
C. 8.39 %
Explanation:
Given:
Molar concentration = 0.25 M
Molar weight of sucrose = 342.296 g/mol
Density of solution = 1.02 g/mL
Mass of water = 934.4 g.
Density in g/l = 1.020 g/ml * 1000ml/1 l
= 1020 g/l
Mass of solution in 1 l of solution = 1020 g
Mass of solution = mass of solvent + mass of solute
Mass of sucrose = 1020 - 934.4
= 85.6 g of sucrose in 1 l of solution.
A.
Density of sucrose = mass/volume
= molar mass/molar concentration
= 342.296 * 0.25
= 85.6 g/l
Number of moles = mass/molar mass
= 85.6/342.296
= 0.25 mol
B.
Molality = number of moles of solute/mass of solvent
= 0.25/934.4
= 0.00027 mol/g
C.
% mass of sucrose = mass of sucrose/total mass of solution * 100
= 85.6/1020 * 100
= 8.39 %