An ore sample is found to contain 10.500000 g of cobalt and 87.3 g waste rock (gangue). What is the percent by mass of cobalt in the ore?

Me i dont know what to do! the table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

How many moles of cu are needed to react with 5.8 moles of agno3? cu + 2 agno3 → cu(no3)2 + 2 ag

A2-kg bowling ball is 1 meter off the ground on a post when it falls. just before it reaches the ground,its traveling 4.4 m/s. assuming that there is no air resistant, which statement is true a. the initial potential energy is less then the final kinetic energy b. the mechanical energy is not conserved c. the mechanical energy is conserved d. the initial potential energy is greater than the final kinetic energy