Energy Consumption

In 2000, the US accounted for one-fourth of the total world energy consumption and both the US and world rates were growing at a 3.5 percent annual rate. Suppose the US cut its growth rate to 1.1 percent, while the rest of the world growth propelled by the needs of developing countries, continued to increase by the historic rate. What would be the US share of total consumption in 2050 (in percent)?

What reasons could there be for different water sample results at four sites along a river?

What reasons could there be for different water sample results at four sites along a river? (see files attached with data)

Easy 3-part problem - photosynthesis reaction

1) Photosynthesis is estimated to produce 339.99999 g (dry weight) of plant matter per square meter, 50% of which is carbon. Calculate the total number of grams of carbon "fixed" each year by 1000 square meters. 2) The photosynthetic reaction can be represented as: 6CO2 + 6H2O -> C6H12O6 + 6O2 Of the glucose produced, 40.0% is used by the plant to fuel respiration; the rest is converted to plant matter. Calculate the total moles of glucose produced annually in our reference 1000 square meter area. 3) Each mole of glucose produced represents the absorption of 2802.999 kJ of solar energy. If the average energy available from the sunlight over an eight-month period is 1.0 kJ/cm2 per day, wh... click for more

Simple half-life question (based on disintegration per minute)

The well-preserved remains of a now extinct woolly mammoth is entombed in the permafrost lands of Siberia. Scientists have conducted carbon dating experiments on plant debris found in the stomachs of this mammoth. The C-14 activity of the mammoths was measured at 1.499999999999999 disintegration per minute per gram of carbon. How many years ago did the Siberian mammoth die?

Ahort chem problem - involves precipitation

How much Fe++ could be present in water containing 1.4 x 1e-02 M HCO3- (bicarbonate) without causing the precipitation of FeCO3 (Ksp=10**(-10.7))