Q1)
molarity is defined as the number of moles of solute in 1 L of solution.
the NaCl solution volume is 1.00 L
number of moles NaCl = NaCl mass present / molar mass of NaCl
NaCl moles = 112 g / 58.5 g/mol = 1.91 mol
the number of moles of NaCl in 1.00 L of solution is - 1.91 mol
therefore molarity of NaCl is 1.91 M
Q2)
molality is defined as the number of moles of solute in 1 kg of solvent.
density is mass per volume.
density of the solution is 1.08 g/mL.
therefore mass of the solution is = density x volume
mass = 1.08 g/mL x 1000 mL = 1080 g
since we have to find the moles in 1 kg of solvent
mass of solvent = 1080 g - 112 g = 968 g
number of moles of NaCl in 968 g of solvent - 1.91 mol
therefore number of NaCl moles in 1000 g - (1.91 mol / 968 g) x 1000 g/kg = 1.97 mol/kg
molality of NaCl solution is 1.97 mol/kg
Q3)
mass percentage is the percentage of mass of solute by total mass of the solution
mass percentage of solution = mass of solute / total mass of the solution
mass of solute = 112 g
total mass of solution = 1080 g
mass % of NaCl = 112 g / 1080 g x 100%
therefore mass % of NaCl = 10.4 %
answer is 10.4 %
Answer:
20 x (6.022 x 10^23) atoms in 20 moles of Calcium.
Explanation:
A mole contains 6.022 x 10^23 atoms, which is also known as Avogadro's number, and this number is same for each element. So, there are 20 x (6.022 x 10^23) atoms in 20 moles of Calcium.
Answer:
A
Explanation:
CH4+O2-CO2+ H20
that mean methane has burn in oxygen to produce CO2
Answer:
Option A, light energy from the sun
Explanation:
In the process of photosynthesis, the energy from sun in the form of light and heat is taken to undergo glycolysis and prepare glucose/starch (chemical).
Thus, the light and heat energy of sun is converted into the chemical energy.
Option B and C are incorrect because no kinetic energy or chemical energy is taken from any source.
Option D is also incorrect because heat is taken but it is not taken from the surrounding environment. The source of heat energy is sun.
Thus, only option A is correct
