Answer:
A chemist searches for new knowledge about chemicals and use it to improve the way we live. He or she may develop products such as synthetic fibers, drugs and cosmetics. Chemists create processes, including all refining and petrochemical processing, that reduce energy use and pollution.
There are eight protons in an Oxygen's nucleus.
Answer:
The cat
Explanation:
1) You need to find how many meters per second each thing is sprinting, so you can divide the meters by seconds for each.
2) Per second, the sprinter is able to achieve 8 meters, while the cat can do around 10.5 meters. 10.5 is greater than 8, making the cat faster than the sprinter.
Iridium-192 is used in cancer treatment, a small cylindrical piece of 192 Ir, 0.6 mm in diameter (0.3mm radius) and 3.5 mm long, is surgically inserted into the tumor. if the density of iridium is 22.42 g/cm3, how many iridium atoms are present in the sample?
Let us start by computing for the volume of the cylinder. V = π(r^2)*h where r and h are the radius and height of the cylinder, respectively. Let's convert all given dimensions to cm first. Radius = 0.03 cm, height is 0.35cm long.
V = π * (0.03cm)^2 * 0.35 cm = 9.896*10^-4 cm^3
Now we have the volume of 192-Ir, let's use the density provided to get it's mass, and once we have the mass let's use the molar mass to get the amount of moles. After getting the amount of moles, we use Avogadro's number to convert moles into number of atoms. See the calculation below and see if all units "cancel":
9.896*10^-4 cm^3 * (22.42 g/cm3) * (1 mole / 191.963 g) * (6.022x10^23 atoms /mole)
= 6.96 x 10^19 atoms of Ir-122 are present.
