Chemistry Answers

A fixed mass of a gas occupies 100cm cubed ,at-15cm cubed and 650mmHg pressure at what temperature will it have a volume of 150cm cubed if the pressure is adjusted to 680 mmHg?

Oxygen gas inside a 1.5 L gas tank has a pressure of 0.95 atm. Provide the temperature remains constant, how much pressure is needed to reduce it's volume by 1/2

1.The pH sample of human blood was measured to be 7.41 at 25 degrees celsius. Calculate the hydrogen ion concentration, H' and hydroxide ion, OH for the sample.

Find the molarity of 45.0 g NaC1 in 500.0 mL

What is the trend in ionic radius from potassium to sodium

Calculate the free energy change for the reaction shown below at 25oC. 2NO + O2 → NO3

A CAPE Chemistry student sought to determine the solubility product, Ksp of calcium hydroxide by titrating saturated solution of Ca(OH)2 against standardized hydrochloric acid solution, HCl. The saturated Ca(OH)2 solution was filtered, to remove excess solute, and 25mL aliquots were titrated against 0.10M HCl solution using bromothymol blue indicator.

State the colour change the student observed as the end-point was reached. 

Calculate the concentration of Calcium Hydroxide.

Write the Ksp expression for Ca(OH)2.

Use the equilibrium expression for the dissolution of Ca(OH)2 to determine the concentration of Ca2+ and OH–.

Calculate the Ksp for calcium hydroxide (state the units).

The value the student calculated deviated significantly from the accepted value. The reason given was 

‘some of the excess solute got into the filtrate during filtration of the saturated calcium hydroxide’.

State how this could have affected the Ksp value.

State one other factor that could have affected the Ksp value.

https://mir74.ru/22964-pozhiloy-gribnik-zabludivshiysya-v-okrestnostyah-zlatousta-poltory-nedeli-nazad-nayden-mertvym.html

9. Shore has developed systematic procedures for making boron hydrides in good yield taking advantage of ;

A. Pyrolysis of diborane. B. Acidity of -H.

C. Hydrogen abstraction. D. Abstraction of H- .

E. Thermal decomposition.