Answer:
"The number of air molecules above a surface determines air pressure. As the number of molecules increases, they exert more pressure on a surface, and the total atmospheric pressure increases. By contrast, if the number of molecules decreases, so too does the air pressure."
Answer:
100. mL
Explanation:
Step 1: Write the balanced equation for the double displacement reaction
CaCl₂ + Na₂CO₃ ⇒ 2 NaCl + CaCO₃
Step 2: Calculate the moles corresponding to 1.00 g of CaCO₃
The molar mass of CaCO₃ is 100.09 g/mol.
1.00 g × 1 mol/100.09 g = 0.0100 mol
Step 3: Calculate the moles of CaCl₂ required to produce 0.0100 moles of CaCO₃
The molar ratio of CaCl₂ to CaCO₃ is 1:1. The moles of CaCl₂ required are 1/1 × 0.0100 mol = 0.0100 mol.
Step 4: Calculate the volume of 0.100 M CaCl₂ that contains 0.0100 mol
0.0100 mol × 1 L/0.100 mol × 1000 mL/1 L = 100. mL
Answer:- B- 
Explanations:- Sharing of electrons takes place between non metals and the bond formed by the sharing of electrons is known as covalent bond. In first choice we only have a zinc metal and so no sharing of electrons would be possible here.
In third choice we have NaCl. Na is a metal and Cl is a non metal. The property of metals is to transfer its valence electrons to the non metal and the bond formed is known as ionic bond. So, third choice is also not correct.
In choice B we have sulfate ion that has sulfur and oxygen atoms and both of these are non metals. So, sharing of electrons is present here between the S and O atoms and covalent bonds are formed.
So, choice B- is the right answer.
An isotope is one of two or more forms of the same chemical element. Different isotopes of an element have the same number of protons in the nucleus, giving them the same atomic number, but a different number of neutrons giving each elemental isotope a different atomic weight.
