A pound is approximately 0.45 kilogram. A person weighs 87 kilograms. What is the persons weight, in pounds, when expressed to the correct number of significant figures.

What charges do the following ions have? Mg Al O K N Br

Which process is a chemical change? 1. freezing of liquid water to solid ice 2. condensation of gaseous steam to liquid water 3. boiling of liquid water to gaseous steam 4. decomposing of water to hydrogen gas and oxygen gas

In the science lab, students are testing solutions as acids or bases. the ph level of solution "x" was determined to be an 8. what is solution "x"?

Which of the following would have the highest average kinetic energy A. Cl2 gas at 35 C B. F2 gas at 15 C C. O2 gas at 25 C D. N2 gas at 50 C

Which of these is not an obstacle to the future of space exploration?

Can matter exist at a temperature below absolute zero? Why or why not?

When group 17 elements become ions they have a charge of?

The first periodic table developed by Mendeleev was not completely accurate, but was a great step toward accomplishing the periodic table of elements we use today. Explain how the modern periodic table is credible today because of Mendeleev's work.

For the reaction represented by the equation 2hno3 + mg (oh) 2® mg (no3) 2 + 2h2o, how many grams of magnesium nitrate are produced from 8.00 mol of nitric acid, hno3, and an excess of mg (oh) 2?

What type of bond is between sodium and oxygen