Answer:
2.77 mol/kg
Explanation:
Molality is a sort of concentration that indicates the moles of solute in 1kg of solvent. In this case our solvent is water and, if we consider water's density as 1g/mL, we determine that the mass of solvent is 750 g.
We convert the mass to kg → 750 g . 1kg /1000g = 0.750 kg
Our solute is the NaOH → 83 g.
We convert the mass to moles → 83 g . 1mol /40g = 2.075 mol
Molality (mol/kg) = 2.075 mol / 0.75kg = 2.77 m
From the gas law, PV=nRT we can say that P(pressure), V(volume) and T (temperature) are related to each other. The initial volume of sample is 408 ml
Given that initial volume of the sample = V1
initial pressure of the sample = 0.92atm
initial temperature of the sample = 23.2oC
Final pressure of the sample = 1.3atm
Final temperature of the sample = 40.1 oC
Final volume of the sample = 500ml = 0.5L
Using the relation P1V1/T1 = P2V2/T2
V1 = 1.3x0.5x23.2/40.1x0.92 = 15.08/36.892 = 0.408
Hence the initial volume of sample = 408 ml
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Answer: the answer is B
Explanation: i go to connexus i had this question
1 mole of NO2= 7 + (8×2)= 7 + 16 = 23g
81g of NO2 = 81÷23 = 3.5217
Ans = 3.5 moles ...//
When a substance melts, the solid gains heat, and the motion of the particles increases (particles move faster in liquid form than in solid form).