12.5%
Three half lives pass. 50% -> 25% -> 12.5%
True is does make up 90 percent
Answer:
A precipitation reaction produces an insoluble solid as a result of the reaction of two dissolved chemicals in a solution. The insoluble solid, called a precipitate, sinks to the bottom of the solution or stays in suspension as cloudy particles.
Explanation: ur welcom
Set up your units to algebraically cancel out the original unit, and end up with the units of the answer in the final numerator. We'll first convert to moles by using Avogadro's number, then the atomic mass of tungsten (W) from the periodic table, since the mass, in grams, of one mole of any element is the atomic mass number:
2.1x10∧24 atoms W x (1 mole/6.022x10∧23 atoms) x (183.84g/1 mole) = 641.089 grams
Since your given number has only two significant figures (2.1), your answer should also only express in 2 sig figs: 6.4x10∧2 grams
