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How many moles of KCl are produced from 2.50 moles K ?
When an electron is added to the valence shell
A sample of gas at 28.0 °C has a volume of 6.20 L and exerts a pressure of 720.0 mmHg. How many moles of gas are in the sample?
A water sample is not alkaline to phenolphthalein however 25ml of the sample on titration required 4.5ml , 0.02N HCL for methyl orange end point. Determine the types and amount of alkalinity present in the sample? (Find P&M, amount of alkalinity)
The N in a 0.4984-g sample of organic material is converted to NH4HSO4 by digestion with concentrated H2SO4. If the NH4+ ions are precipitated as (NH4)2PtCl6 and the precipitate is ignited to Pt, what is the percentage of N in the sample if the Pt weighs 0.1876 g?
Calculate the pH of a solution which contains 2.0 x 10-3 M sodium acetate and 3.3 x 10-2 M acetic acid in a liter solution. The pKa is 4.74.
What is the ratio of the salt & acid concentration if the solution has a pH of 4.5 & pKa of 4.76?
Calculate the pH of a solution which contains 3.7 x10−2 mole of HAc & 4.8 x 10−2 mole of Na Ac in a liter of solution containing pka 9.26.
A buffer is prepared using 0.28 M HNO2 and 0.23 M NO2 − . The pKa for HNO2 is 3.34. What is the pH of
this buffer after the addition of 0.05 M HCl?
) Calculate the entropy change at a constant pressure of 1 atm when one mole of liquid
NH3 at -40 is transformed to the gaseous state at 200 using the following data: ℃ ℃
Cp for NH3 (l) = 17.9 Cal K-1 mol-1 ; Cp for NH3(g) = (8.04 + 7.0 x 10-4 T + 5.1 x 10-6
T 2
)Cal K-1 mol-1 ; Boiling Point of NH3 (g) = 239.7 K; ΔvapH239.7 = 5560 Cal mol-1
