4. If 175 undecayed nuclei remain from a sample of 2800 nuclei, how many half-

lives have passed? (Show your work.) *

Your answer

A sample of metal has a mass of 17.20 g and a volume of 5.59 mm what is the density of this mass

During vaporization, a substance changes from a liquid to a (n) blank. (fill in the blank)

What can be described as the breaking of old bonds and forming of new ones? A. chemical reaction B. atomic state C. conduction D. induction

You are asked to determine the mass of a piece of copper using its reported density

The compound calcium cyanamide (CaNCN) is used as a nitrogen source for crops. To obtain this compound, calcium carbide is reacted with nitrogen at high temperatures. CaC2 (s) + N2 (g) CaNCN (s) + C (s) What mass of CaNCN can be produced if 7.

Trevor watches as a freight train passes. He counts eight identical black railroad cars, then a red car, followed by several more black cars.

How long does a hydrogen bond last in water

If the body temperature of a person is recorded as 37°c, what is the person's body temperature in k? round your answer to the nearest whole number.

Pf3cl2 is a nonpolar molecule. based on this information, determine the f-p-f bond angle, the cl-p-cl bond angle, and the f-p-cl bond angle. enter the number of degrees of the f-p-f, cl-p-cl, and f-p-cl bond angles, separated by commas (e. g.

What is the empirical formula of a substance that contains 2.64g of C, 0.444g H and 3.52g of O