A cross-country skier can complete a 7.5 km race in 45 min. What is the skier's average speed? km/h

Select all that apply. What is common about the elements of a period? They have the same number of electron shells. They have similar chemical characteristics. They have similar physical characteristics. They transition from a metal to noble gas.

How many atoms are in a sample of carbon weighing 16 grams? Round your answer to two decimal places. Group of answer choices 9.63 x 10^24 atoms 1.33 atoms 2.20 x 10^22 atoms 8.01 x 10^23 atoms

Hemoglobin, the oxygen-carrying protein in red blood cells, has four iron atoms per molecules ad contains 0.340 percent iron by mass. calculate the molar mass of hemoglobin

If 2.06 mL of seawater contains about 0.446 moles of gold, how many atoms of gold are in that volume of seawater?

Based on their formulas which of these compounds is not likely to be an ionic compound: KBr, SO2, or AlCl3? Explain.

Science is a unique field of thought because it relies on to describe the world. •Observations and experim •Teachers and students •Books and writings •Scientists and statements

Hemoglobin, a protein in red blood cells, carries o2 from the lungs to the body's cells. iron (as ferrous ion, fe2+) makes up 0.33 mass % of hemoglobin. if the molar mass of hemoglobin is 6.8 Ã 104 g/mol, how many fe2 + ions are in one molecule?

What could you predict about a methane molecule that would most likely be made by using both the quantum model of the atom and John Dalton's model?

What is the molar mass of an unknown hydrocarbon whose density is measured to be 1.97 g/l at stp?

Which is an example of flow of heat through conduction