How can the atomic number and mass number be used to determine the amount of each subatomic particle present in an atom of a given element?

4. If 175 undecayed nuclei remain from a sample of 2800 nuclei, how many half- lives have passed? (Show your work.) * Your answer

Which element is the most active nonmetal?

The following reaction: NO2 (g) - -> NO (g) 1/2 O2 (g) is second-order in the reactant. The rate constant for this reaction is 3.40 L/mol*min. Determine the time needed for the concentration of NO2 to decrease from 2.00 M to 1.50 M.

At a temperature of 393 K, the temperature of a sample of nitrogen is 1.07 atm what will the pressure be at a temperature of 478 K

Given the balanced equations representing two chemical reactions:Cl2 + 2NaBr - - - > 2NaCl + Br2 2NaCl---> 2Na + Cl2 Which types of chemical reactions are represented by these equations?

State the relationship between the number of electrons in a carbon-nitrogen bond and carbon-nitrogen bond energy

What are the characteristics of bones?

If 294 grams of FeS2 is allowed ti react with 176 grams of O2 according to the following equation how many grams of Fe2O3 are produced? FeS2 + O2 = Fe2O3 + SO2

Convert 3.57 moles of aluminum to grams

An average microwave uses a frequency of 2.54 GHz. How much energy is emitted?