The number of valence electrons of the element with the electron configuration 1s22s22p63s23p1 is :

When hafnium metal is heated in an atmosphere of chlorine gas, the product of the reaction is found to contain 62.2% hf by mass and 37.4% cl by mass. what is the empirical formula for this compound?

Defition of chemical change

NADH is also used by cells when making certain molecules. Based on your knowledge of the role of NADH in cellular respiration, what do you think NADH's role is in biosynthesis of molecules?

Valence electrons are: O a. Electrons that have been lost in an atom O b. Electrons in the nucleus of an atom O c. electrons in the outer-most shell of an atom O d. electrons in the inner-most shell of an atom

What factors affect the rate of a chemical reaction?

Can someone reword this? A magnetic substance has magnetic fields. These fields start at the North Pole wrap around the magnet, and terminate at the south pole of the magnet. All magnetic substances have north and south poles

Which of these is produced when fossil fuels are burned? A) oxygen Eliminate B) nitrogen C) hydrogen D) carbon dioxide

Predict the sign of ΔSsys for each of the following processes. Which are positive? (a) Gasoline vapors mix with air in a car engine. (b) Hot air expands. (c) Humidity condenses in cold air.

A system consists of two components, each of which must activate if the system is to activate. One component has a reliability of. 99. The other has a reliability of. 95. The components are independent of one another with respect to reliability.

Which of the following energy level changes for an electron is most energetic? 3 → 2 5 → 2 4 → 2