Which is evidence that scientists use to support the big bang theory?
a.
there is constant cosmic background radiation.
b.
galaxies are moving toward each other.
c.
a loud explosion can be heard in the radio frequencies everywhere in the universe.
d.
hydrogen and helium are the most abundant elements in the universe.

You are performing an experiment in a lab to attempt a new method of producing pure elements from compounds. the only problem is that you do not know what element will form. by your previous calculations you know that you will have 6.3 moles of product. when it is complete, you weigh it and determine you have 604.4 grams. what element have you produced?

Using a value of ksp = 1.8 x 10-2 for the reaction pbcl2 pb+2(aq) + 2cl -(aq). if the value of ksp was determined to be only 1.2 x 10-2: too much solid has dissolved. additional precipitate is forming. the solution is unsaturated. the ions are now combining to reduce their concentrations.

Which change to the system wood cause the freely-moving piston to lower?