18. What is the density of a substance with a mass of 0.90 kg and a volume of 1.2 mL? 21. An oxygen tank in the lab has a pressure of 12 atm at 250C. If the pressure inside the gas tank exceeds 25 atm, the tank will explode. If a fire occurs in the lab, raising the temperature of the gas inside the cylinder to 398oC, will the tank explode?

Ageologist determines that a sample of a mineral can't be scratched by a steel nail but can be scratched by a masonry drill bit. based on this information, the sample mineral has to be softer than a. orthoclase. b. fluorite. c. apatite. d. corundum.

Select the correct answer from each drop-down menu.describe what happens to a carbon-11 atom when it undergoes positron emission.the decay of a carbon-11 atom _1_, and this causes it to emit _2_.options for 1: > changes a neutron into a proton> changes a proton into a neutron> is hit with a neutron> reconfigures its protons and neutronsoptions for 2: > a negatively charged electron-sized particle> a positively charged election-sized particle> two atoms and several neutrons> two neutrons and two protons

In the space, show a correct numerical setup for calculating the number of moles of co2 present in 11 grams of co2