Key to the study of Chemistry

A 25.0-g sample of each of three unknown metals is added to 25.0 mL of water in graduated cylinders A, B, and C, and the final volumes are depicted in the circles below. Given their densities, identify the metal in each cylinder: zinc ( 7.14g/ml ), iron ( 7.87g/ml ), nickel ( 8.91g/ml ).

Perform the following conversions: 

(a) 106°F (the body temperature of many birds) to K and °C 

(b) 3410°C (the melting point of tungsten, the highest for any metallic element) to K and °F 

(c) 6.1ᵡ10³ K (the surface temperature of the Sun) to °F and °C

A cylindrical tube 9.5 cm high and 0.85 cm in diameter is used to collect blood samples. How many cubic decimeters (dm³) of blood can it hold (V of a cylinder = πr²h)?

Copper can be drawn into thin wires. How many meters of 34-gauge wire (diameter = 6.304ᵡ10^-3 in) can be produced from the copper in 5.01 lb of covellite, an ore of copper that is 66% copper by mass? (Hint: Treat the wire as a cylinder: V of cylinder = πr² h; d of copper = 8.95 g/cm³.)

Convert the following into correct scientific notation: 

(a)  $\mathbf{802}\mathbf{.}\mathbf{5}\mathbf{\times }{\mathbf{10}}^{\mathbf{2}}$

(b)  $\mathbf{1009}\mathbf{.}\mathbf{8}\mathbf{\times }{\mathbf{10}}^{\mathbf{-}\mathbf{6}}$

(c) $\mathbf{0}\mathbf{.}\mathbf{077}\mathbf{\times }{\mathbf{10}}^{\mathbf{-}\mathbf{9}}$

Convert the following into correct scientific notation: 

(a)  $\mathbf{14}\mathbf{.}\mathbf{3}\mathbf{\times }{\mathbf{10}}^{\mathbf{1}}$

(b) $\mathbf{851}\mathbf{\times }{\mathbf{10}}^{\mathbf{-}\mathbf{2}}$

(c) $\mathbf{7500}\mathbf{\times }{\mathbf{10}}^{\mathbf{-}\mathbf{3}}$

Bromine is used to prepare the pesticide methyl bromide and flame retardants for plastic electronic housings. It is recovered from seawater, underground brines, and the Dead sea. The average concentrations of bromine in seawater (d=1.024 g/mL) and the Dead Sea (d=1.22 g/mL) are 0.065g/L and 0.50 g/L, respectively. What is the mass ratio of bromine in the Dead Sea to that in seawater?            

An Olympic- size pool is 50.0m long and 25.0 m wide. 

(a) How many gallons of water (d=1.0g/mL) are needed to fill the pool to an average depth of 4.8 ft? (b) What is the mass (in kg) of water in the pool?

At room temperature (20°C) and pressure, the density of air is 1.189 g/L. An object will float in air if its density is less than that of air. In a buoyancy experiment with a new plastic, a chemist creates a rigid, thin-walled ball that weighs 0.12 g and has a volume of 560 .

(a) Will the ball float if it is evacuated?

(b) Will it float if filled with carbon dioxide (d = 1.830 g/L)?

(c) Will it float if filled with hydrogen (d = 0.0899 g/L)?

(d) Will it float if filled with oxygen (d = 1.330 g/L)?

(e) Will it float if filled with nitrogen (d = 1.165 g/L)? 

(f) For any case that will float, how much weight must be added to make the ball sink?