Calculate the atomic mass of silicon. The three silicon isotopes have atomic masses and relative abundances of 27.9769 amu (92.2297%), 28.9765 amu (4.6832%) and 29.9738 amu (3.0872%). Show your work.

Occurs when the moon passes between the sun and the earth

Consider the burning of gasoline and the evaporation of gasoline. which process represents a chemical change and which represents a physical change?

Write the following as a ratio in the simplest form: 15 winners out of 120 raffle entries.

When compared to sulfur-32, sulfur-34 has more - ?

If a fossil sample originally contained 5 grams of carbon-14 and the half-life of carbon-14 is 5,700 years. After 11,400 years how many grams of carbon-14 would remain

Student follow up The ionic equation for the reaction between zinc and sulfuric acid is. Zn (s) + 2H (aq) - - Zn" (aq) + H2 (g) a State what has been oxidised in this reaction. Explain your answer in terms of electrons.

What kind of group 1 atoms are the most reactive? a. Small atoms c. Atoms with the most electrons in the valence level b. Large atoms d. Atoms at the top of the periodic table

What does it mean when there are 2.3 x 10-4 moles?

Electric force is an A. attraction and repulsion between protons and electrons . B. attraction and repulsion between protons and neutrons. C. attraction and repulsion between neutrons and electrons.

A salt crystal has a mass of 0.18 mg. how many nacl formula units does it contain?