# Chemistry tutorials & FAQs!

#### emc4444

chemical
1 . In a 1 liter at room temperature are in equilibrium T0C 2 mol NH3 , O2 and 2 mol 1 mol H2 . according to the equation : 4NH3 ( g ) 3O2 ( g ) 2N2 = ( g ) 6H2O ( g ) . Determine the price of the equilibrium constant K at this temperature ?

2 . Known an equilibrium reaction 2A B = A2B . On the initial conditions in 1 liter benjana there are 2 moles of A and 2 moles of B. If in equilibrium there are 0.5 moles of A , then the equilibrium constant is ?

3 . In 1 liter containers equilibrium reaction H2 ( g ) I2 ( g ) = 2HI ( g ) at a price of KC = 0.5 at a certain temperature . I2 concentration necessary for equilibrium when there PMH2 and QMHI is ?

4 . 0.1 mol HBr some input into 1 liter flask and decomposes according to the reaction 2HBr ( g ) = H2 ( g ) Br2 ( g ) . If 0.015 mol Br2 formed , then the equilibrium constant is equal to ?

5 . In the space of 5 litr reacted with 0.5 mol 0.4 mol N2 O2 gas according to the reaction : N2 ( g ) O2 ( g ) 2NO ( g ) . Having reached a state of equilibrium 0.2 mol gas formed NO . K is the price ?

#### RhondaBristol

IV. Potential of Hydrogen (pH)
The pH is the measurement of basicity/acidity in a solution. The following scale represents the different values and gives us common examples: Solutions with a pH under 7 are said to be acid while solution with a pH over 7 are said to be basic. A basic solution can be as dangerous if not more than an acid solution. Also, take note that the temperature of a solution also slightly affects its pH.

When an acid gets dissolved into water, the pH of the solution drops under 7, depending on the pH of the used acid. Stronger acids drops the pH more quickly, while stronger bases raises the pH more quickly. That's where the concept of neutralization takes life: you need a strong base to neutralize (bring back to a pH of 7) a strong acid. When a solution is successfully neutralized, it creates water (H20) and salt (NaCl). The balanced equation of a neutralization is the following:
HCl [acid] + Na(OH) [base] -> H2O [water] + NaCl [salt].
This can help me a lot. Thank you.

Thank you!

#### Alina

Hello,

I need help with the following question:

Write a procedure that would follow to demonstrate the effect of increasingly higher concentrations of hydrochloric acid on its rate of reaction with antacid tablets. Can only use materials listed:
- Hydrochloric acid (with a concentration of 1.0 mol/L)
- Distilled water
- Antacid tablets (calcium carbonate)
- A mortar and pestle
- Graduated cylinders (10 mL, 100 mL sizes)
- Test tubes and beakers
- Balance and measuring pan
- Hot plate (heat source)
- Thermometer
- Stopwatch or other timing device
- Ice-water bath
- Scoop

I realize that hydrochloric acid needs to be diluted with water in 4 beakers. Each beaker will contain different amount of HCL in it. Im having a hard with starting the procedure please assist.

Thanks

#### arkajit

Here is another wonderful chemistry website containing 50 calculators and unit converters etc.

http://calistry.org

here are some calculators, have a look and please give your suggestions

1. Balancing Chemical Equations : This is chemical equation balancer , it can be used for chemical equations like "NaOH + H2SO4 = Na2SO4 + H2O".
visit: http://calistry.org/calculate/balanceChemicalEquation
2. Molecular Weight Calculator : Also displays a cool Pie chart on the % weight contribution of different elements. Amino acid sequences are also supported (eg. ProValGlyTyr )
visit: http://calistry.org/molecular-Weight-Calculate 3. Effective Nuclear Charge Calculator: This based on the Slater's rule:
visit: http://calistry.org/calculate/slaterRuleCalculator
4. Van Der Waals equation calculator: http://calistry.org/calculate/vanDerWaalsCalculator
5. Gay Lussac Calculator: http://calistry.org/calculate/gayLussacsLawCalculator
6. Wave length visualizer : http://calistry.org/wavelengthVisibleSpectrum Here
there are 50 more in the site

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