Why are standards needed for measured quantities?

How many grams are in 6.53 moles of Pb

Do the phases of the moon really affect human behavior. Defend your answer scientifically and site sources.

Which sample is a pure substance? (A) a test tube of zinc oxide (B) a container of zinc and oxygen (C) flask of pond water (D) a jar of soil

In a reaction involving I-, I 2 and starch, you observe the rate at which a blue color appears over time. Which statement is true? A. You are observing the disappearance of products over time. B.

What causes photons to be emitted from excited atoms

The mixing of which pair of reactants will result in a precipitation reaction? the mixing of which pair of reactants will result in a precipitation reaction?

A balloon has 18.9 moles of hydrogen gas at a volume of 428 L. What would the volume of the gas be if the balloon had 14.0 moles of hydrogen gas left after 1 day?

An analytical chemist is titrating 242.5 mL of a 1.200 M solution of hydrazoic acid HN3 with a 0.3400 M solution of NaOH. The pKa of hydrazoic acid is 4.72. Calculate the pH of the acid solution after the chemist has added 1006.

A gas stream contains 18.0 mol% hexane and the remainder nitrogen. the stream flows to a condenser, where its temperature is reduced and some of the hexane is liquefied. the hexane mole fraction in the gas stream leaving the condenser is 0.0500.

What type of solution is aerated water. why is it so.