Climate is one of the factors that determines where different species of plants and animals can live, so paleontologists look for clues to a location's ancient climate in the types of fossil plants and animals they find there. For example, no modern crocodile species lives in a climate with long periods of freezing temperatures, so scientists hypothesize that ancient crocodiles had the same requirement for year round warmth. That leads them to consider the 110-million-year-old crocodile fossils from the Washington, D.C. to be part of a large body of circumstantial evidence that temperatures there were warm year round during the Early Cretaceous. Similarly, coal beds and fossil trees in the Arctic Slope of Alaska are among the many clues that Alaskan temperatures were very warm during the Late Cretaceous.
Answer:
There are 9.8 ×1021. formula units in 10,005.8gCaO
Answer:
0.2
Explanation:
Given parameters:
Mass of helium = 0.628g
Mass of neon = 11.491g
Mass of argon = 7.613g
Unknown:
Mole fraction of neon = ?
Solution:
The mole fraction of an element is the number of moles of that element to the total number of moles in the gas mixture.
We need to calculate the number of moles of each element first;
Number of moles = 
Molar mass of Helium = 4g/mol
Molar mass of Neon = 20g/mol
Molar mass of Argon = 40g/mol
Number of moles of He = 
= 0.16moles
Number of moles of Ne = 
= 0.58moles
Number of moles of Ar = 
= 0.19moles
Total number of moles = 0.16moles + 0.58moles + 0.19moles = 0.93moles
Mole fraction Neon = 
= 0.2
I have attached a photo of the structure.
You can get better at solving problems like this by practicing a lot!
A food provides enough energy to raise the temperature of 2000 grams of water by 10°c contains 20 KCa.
1 Calorie is the amount of heat needed to elevate one gram of water to one degree Celsius temperature at one atmosphere of pressure.
The term "kilocalorie" is used to describe the amount of energy needed to increase 1 L of water's temperature by one degree Celsius at sea level.
Given
Mass of water (m) = 2000 g
Temp raise (ΔT) = 10°C
Heat capacity of water (C) = 1 calorie/g-C
Formula used
Heat (ΔH) = m × C × ΔT
= 2000 × 10 = 20000 C
In Kilo calories
20000 C = 20000/1000 = 20 KCa
Hence, a food provides enough energy to raise the temperature of 2000 grams of water by 10°c contains 20 KCa.
Learn more about Calories here brainly.com/question/23688200
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