You find a radioactive substance in the chemistry storage locker. You measure the mass of the substance and find that it is 5 grams. You do some research and find that this substance has a half-life of 10 seconds. How much mass of this substance was in the chemistry storage locker 1 hour before you found it? 0 10 grams O 40 grams O 120 grams O 320 grams O 640 grams O It is impossible to know the starting mass of any substance due to radioactive day.​

Asap 1. which surface feature of the moon is characterized by mountainous areas? question options: maria terrae regolith craters 2.which statement describes surface features called maria on the moon? question options: layers of dust and rock deep areas of cooled lava deep, rocky and barren valleys highlands and mountainous areas

How many hydrogen (h) atoms are in one molecule of sulfuric acid, h2so4? (1 points) 1 2 4 7

The speed of sound in ice, water, and steam is shown. what best explains the speed of sound in different states of matter? sound travels fastest in ice because energy is easier to transfer when the molecules are close together. sound travels slowest in steam because the sound has to move around the gas molecules that are far apart. sound travels fastest in ice because the temperature of solids is always greater, so the heat transfers the sound energy. sound travels slowest in steam because the pressure is so great the sound cannot travel though the steam particles.