The CH4 molecule has the lowest molecular weight, so it has the lowest boiling point.
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Answer:
A. there is an isotope of lanthanum with an atomic mass of 138.9
Explanation:
By knowing the different atomic masses of both Lanthanum atoms, we can not tell anything about their occurence in nature. Therefore, all the last three options are incorrect. Because, the atomic mass does not tell anything about the availability or natural abundance of an element.
Now, the isotopes of an element are those elements, which have same number of electrons and protons as the original element, but different number of neutrons. Therefore, they have same atomic number but, different atomic weight or atomic masses.
Hence, by looking at an elements having same atomic number, but different atomic masses, we can identify them as isotopes.
Thus, the correct option is:
<u>A. there is an isotope of lanthanum with an atomic mass of 138.9.</u>
The experimental mole ratio of silver chloride to barium chloride is calculated as below
fin the mole of each compound
mole= mass/molar mass
moles of AgCl = 14.5g/142.5 g/mol = 0.102 moles of AgCl
moles of BaCl2 = 10.2 g/208 g/mol = 0.049 moles of BaCl2
find the mole ratio by dividing each mole with the smallest mole(0.049)
AgCl= 0.102/0.049 =2
BaCl2 = 0.049/0.049 =1
therefore the mole ratio AgCl to BaCl2 is 2 :1
Answer:
B. Carry oxygen, nutrients, waste, & to fight pathogens
Explanation:
The circulatory system refers to all organs and tissues involved in carrying blood and lymph around the body.
The circulatory system carries oxygenated blood from the heart to cells and deoxygenated blood back to the heart.
Nutrients are carried in the blood to cells in different parts of the body and waste products are also carried from cells in the blood.
White blood cells is a component of blood in the circulatory system that fights off diseases.
Answer:
Zirconium
Explanation:
Given that,
Mass number = 92
No of neutrons = 52
Mass number is the sum of the number of protons and neutrons. We can find the number of protons.
92 = 52 + P
P = 40
Atomic number is equal to the number of protons. It means that the atomic no of the element is 40. The element is Zirconium whose atomic number is 40 and mass number is 92.