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Lead, Pb, is used in solders and as radiation shield. It adopts the face centered cubic unit structure with each of the atom having a diameter of 0.35 nanometer. Find the theoretical density of lead if the molecular weight of this metal is 207.2 g/mol.
In an investigation to determine the solubility of NaCl in water, methanol and hexane, a student adde 40.0 g of NaCl
to 100.0 ml of each liquid maintained at a temperature of
25’ c.after 2 minutes of stirring each mixture, the mass of undissolved salt was determined through filtering the mixture and weighing the residue.the results of the investigation are shown below.
liquid Mass of NaCl (s)
Recovered by filtration
hexane 39.9
methanol 38.6
water 3.85
a .
place the liquids tested in order of their increasing solubility of NaCl
b.
explain the trend in solubility of NaCl in the three liquids using your knowledge of the process by which ionic solids dissolve and the intermolecular forces involved.
6Li +1n ---->4 He
3 0 2
Aqueous hydrochloric acid HCl reacts with solid sodium hydroxide NaOH to produce aqueous sodium chloride NaCl and liquid water H2O. If 0.438g of sodium chloride is produced from the reaction of 2.9g of hydrochloric acid and 1.2g of sodium hydroxide, calculate the percent yield of sodium chloride.
Round your answer to 2 significant figures.
The half-life of uranium-235 is much longer than the half-life of carbon-14,
so it can be used to determine the age of rocks that are too old to be dated
with carbon dating.
A scientist finds a fossilised reptile encased in rock containing 82% of the
normal amount of uranium-235. Use the half-life graph above to determine
approximately how long ago the reptile lived.
A sample of marshmallow is combusted directly below a can containing 100g, of water initially at25.0°C. The reaction releases 2.1 kJ of heat energy, all of which is transferred to the water. What is the final temperature of the water? (The specific heat of water is 4.2 J/ (g"C)
Tantalum is a rare, hard, blue-gray, lustrous transition metal that is highly corrosion-resistant. It has a density of 16.4 grams per cubic centimeter and an atomic weight of 180.948 g/mol. What is the atomic radius of Ta if it adopts the body centered cubic unit structure? Express your answer in Å.
For diagram of lithium chloride
