91影视

Of the five elements Sn, Si, Sb, O, Te, which has the most endothermic reaction? (E represents an atom.) What

name is given to the energy for the reaction?

\({\bf{E}}(g) \to {{\bf{E}}^ + }(g){\rm{ }} + {\rm{ }}{{\bf{e}}^ - }\)

Question: In a recent Grand Prix, the winner completed the race with an average speed of 229.8 km/h. What was his speed in miles per hour, meters per second, and feet per second?

Question: Solve these problems about lumber dimensions.

a) TO describe to a European how houses are constructed in the US, the dimensions of 鈥淭wo-by-four鈥� lumber must be converted into metric units. The thickness 脳 width 脳 length dimensions are 1.50 in. 脳 3.50 in. 脳 8.00 ft in the US. What are the dimensions in cm 脳 cm 脳 m?

b) This lumber can be used as vertical studs, which are typically placed 16.0 in. Apart. What is that distance in centimetres?

Question: The mercury content of a stream was believed to be above the minimum considered safe 鈥� 1 part per billion (ppb) by weight. An analysis indicated that the concentration was 0.68 parts per billion. What quantity of mercury in grams was present in 15.0 L of the water, the density of which is 0.998 g/ml? \(\left( {1ppbHg = \frac{{1ngHg}}{{1gwater}}} \right)\)

Question: Calculate the density of aluminum if 27.6 cm³ has a mass of 74.6 g.

Question: Osmium is one of the densest elements known. What is its density if 2.72g has a volume of 0.121 cm³?

Question: Calculate these masses

a) What is the mass of 6.00 cm³ of mercury, density = 13.5939 g/cm³?

b) What is the mass of 25.0 mL octane, density = 0.702 g/cm³?

Question: Calculate these masses

a) What is the mass of 4.00 cm³ of Sodium, density = 0.97 g/cm³?

b) What is the mass of 125 mL gaseous chlorine, density = 3.16 g/L?

Calculate these volumes.

a) What is the volume of 25g of iodine, density = 4.93 g/cm³?

b) What is the volume of 3.28 g gaseous hydrogen, density = 0.089 g/L?

Calculate these volumes.(a) What is the volume of 11.3gmgraphite, density2.25g/cm³?

(b) What is the volume of 39.657gm bromine, density 2.928g/cm³?