A sample contains 25% parent isotope and 75% daughter isotopes. If the half-life of the parent isotope is 72 years, how old is the sample?

You may experiment alone if you apply which of the following safety precautions? A.) Work with safe chemicals B.) Wear all protective equipment C.) Follow all safety protocols D.) Never work alone

To calculate an answer to the correct number of significant figures, you must complete all calculations first and then round your final answer as the very last step. You are asked to calculate the volume of a rectangular prism that has a length of 5.

An object is accelerating if there is a change in speed and which factor? a. time b. position c. direction d. displacement

How are elements in the last column of the periodic table similar? A. They are all solids. O B. They are all liquids. C. They react easily. D. They rarely react.

What is another name for the heat involved in a reaction?

Potassium + Fluorine

Which gas has approximately the same density as c2h6 at stp no nh3 h20 so2?

Identify the combustion reaction. c4h12 + 7o2 ⟶ 6h2o + 4co2 2h2 + o2 ⟶ 2h2o al2s3 ⟶ 2al + 3s cl2 + 2kbr ⟶ 2kcl + br2

A water molecule consists of an oxygen atom and two hydrogen atoms covalently bonded in a bent shape. Oxygen however, attracts the shared electrons more strongly than the hydrogen atoms. This structure leads to which important property of water? a.

How much ko2 is needed to react with 75.0 l of carbon dioxide at - 25˚c and 215 kpa?