Chemistry Answers

Determination of Precision

Apparatus Smallest Calibration, Precision,

10-mL graduated cylinder

50-mLgraduated cylinder

100-mL graduated cylinder

Ruler

The World Meteorological Organization has determined that the world's former record high

temperature 136.4°F (at Al Aziziyah, Libya on September 13, 1922) was miscalculated by about 12.6°F.

What is the correct temperature, in °C, taking into consideration the 12.6°F mistake?

Calculate the average mass of the three samples that have the masses of 10.25 g, 5.5654 g, and

105.4 g. Show your answer with the correct number of significant figures.

110 g of manganese was extracted from 174 g of manganese oxide. (Ar: Mn=55, O=16)

a) What mass of oxygen atoms is this?

110 g of manganese was extracted from 174 g of manganese oxide. (Ar: Mn=55, O=16)

a) What mass of oxygen atoms is this?

1.     How many grams of BaCl₂ should be added to 300 g H₂O so that the freezing point of the solution is lowered – 8.3 ⁰C ? Assume that the BaCl₂  completely dissociates in the solution.

The equilibrium constant, K_c, for the following reaction is 7.00×10^-5 at 673 K.

NH₄I(s) NH₃(g) + HI(g)

Calculate the equilibrium concentration of HI when 0.210 moles of NH₄I(s) are introduced into a 1.00 L vessel at 673 K.

[HI] =   M

The equilibrium constant, K_c, for the following reaction is 1.29×10^-2 at 600 K.

COCl₂(g) CO(g) + Cl₂(g)

Calculate the equilibrium concentrations of reactant and products when 0.351 moles of COCl₂(g) are introduced into a 1.00 L vessel at 600 K.

[COCl₂]=  M

[CO]=  M

[Cl₂]=  M

The density of concentrated ammonia, which is 28.0% w/w NH₃, is 0.899 g/mL. What volume of this reagent should be diluted to 1.0 × 10³ mL to make a solution that is 0.036 M in NH₃? 

A container holds 5grams of ccl4 vapour, calculate the volume of ccl4 present