81. What element has the electron configuration 1s²2s²2pº3s 3p?

a. nitrogen

c. silicon

b. selenium

d. silver

How many moles of lithium oxide will form if 1.68 mol of lithium react?

What is the half life of a radioisotope if you started with 1 gram and 0.250 grams is left after 6 days?

Which of these is an element? A. carbon B. carbon dioxid C. water D. Air

You take a balloon and stick it in a refrigerator. The temperature inside the refrigerator is 4.0 °C and the temperature in your house is 22 °C. The balloon had an original volume of 0.50 L.

A student makes the following two claims about chemical reactions: The result of a chemical reaction is immediately and clearly visible. A chemical reaction transforms one or more substances into new substances.

Suppose there is 0.63 g of HNO3 per 100 mL of a particular solution. What is the concentration of the HNO3 solution in moles per liter?

Of the three thermodynamic quantities, δg, δh, δs, which is most useful for determining spontaneity of a reaction?

Does the density of an object depend on its size? Explain?.

What are two fungal skin infections that humans can contract? pneumonia and ergot disease ergot disease and athlete's foot athlete's foot and ringworm ringworm and pneumonia

A critical biotic factor in Yellowstone National Park is A) geographic isolation B) high elevation C) high temperature in the summer D) population of wolves E) proximity to water