a radioactive substance has a half-life of 10 years. if you start with 30 grams of the substance, how much will remain after 30 years.

Glaicers can only form when

Based on Reference Table J. which two reactants react spontaneously? (I) Mg (s) + ZnCl2 (aq) (2) Cu (s) + FeSO4 (aq) (3) Pb (s) + ZnCl2 (aq) (4) Co (s) + NaCl (aq)

Gaseous methane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water. Suppose 9.3 g of methane is mixed with 52.3 g of oxygen. Calculate the maximum mass of carbon dioxide that could be produced by the chemical reaction.

Germaine wants to know exactly how acidic lemon juice is. Which of these can tell him the pH most precisely? A. pH probe B. indicator solution C. red cabbage juice D. pH paper

Density is a measure of what? How much mass is in a substance (D How much volume is in a substance How much mass per unit of volume is in a substance

Por qué dos iones sodio reemplazan un ion de calcio o de magnesio

How and when did scientists discover cells

How many grams of compound are present in 4.18 grams of K2HPO4

What does the first law of thermodynamics say? A. Energy cannot be stored in any form. B. Energy cannot be created or destroyed. C. Energy cannot move within a system. D. Energy cannot enter or leave a system,

How did the experiement with the iron filings and sulfur compare with the experiment in which copper sulfate pentahydrate was heated? Both resulted in gas formation. Both resulted in color change. Both involved chemical change.