Option 2, Br. I'll go over why all other three options are incorrect.
Option 1 - Krypton is a Noble gas, and so it doesn't need to accept electrons since it has an octet.
Option 3 and 4 - Both Calcium and Barium are alkaline earth metals, and give away electrons, since they only have 2.
-T.B.
Answer:
I cant really see the worksheet can u try again
Explanation:
It is more difficult over easy. Since you haven't figured it out and came here to ask.
Fossils are the preserved remains or traces of animals, plants, and other organisms from the past.
Fossils are important evidence for evolution because they show that life on earth was once different from life found on earth today.
Usually only a portion of an organism is preserved as a fossil, such as body fossils (bones and exoskeletons ), trace fossils (feces and footprints), and chemofossils (biochemical signals).
Paleontologists can determine the age of fossils using methods like radiometric dating and categorize them to determine the evolutionary relationships between organisms.
CH4 (g) + 2O2 (g) --> CO2 (g) + 2H2O (i)
at STP, 1 mol gas = 22.4 L gas. so you have 52.0 L / 22.4 L / mol = 2.32 mol CH4.
According to the balanced reaction, you need 2 mol O2 for every 1 mol CH4. so you need 2 x 2.32 mol = 4.64 mol O2.
hope this help