If 3.0 grams of strontium-90 in a rock sample remained in 1989, approximately how many grams of strontium-90 were present in the original rock sample in 1933?

What is the first element to have p electrons? A. helium B. lithium C. boron D. aluminum

Indicate which of the amino acid residues in the following peptide sequence contains a group that has a negative charge for its most likely charge state at pH 4.

What are 3 stresses that can affect equilibrium?

A powder contains FeSO4 · 7 H2O (molar mass = 278.01 g/mol), among other components. A 3.055 g sample of the powder was dissolved in HNO, and heated to convert all iron to Fe3+.

Two aqueous NaCl solutions of equal volume and concentration were kept in flasks and held at different temperatures. The two solutions were combined in a larger flask. Based on this information, What will be the prediction?

This element has 3 electrons in its Lewis dot structure and is in the 3p orbital section.

In an exothermic reaction, energy is transferred from a. the reactants to the surroundings. c. one reactant to another. b. the surroundings to the reactants. d. the container to the chemicals.

In any chemical compound the elements are always combined in the same proportion by__. a) charge b) mass c) volume d) density

Which would exhibit characteristics of both a metal and a nonmetal? select one: a. si b. ge c. sb d. po e. all of the above exhibit characteristics of both a metal and a nonmetal?

In the synthesis reaction, the white powder produced is magnesium oxide (mgo, mm = 40.3 g/mol). how many moles of magnesium oxide were formed (number of moles = mass (g) / molar mass (g/mol)) ? choose the closest answer. a. 0.21 moles b. 0.