Answer:
A
Explanation:
To label an element correctly using a combination of the symbol, mass number and atomic number furnishes some important information about the element.
We can obtain these information from the element provided that correct labeling of the element is presented. Firstly, after writing the symbol of the element, the atomic number is placed as a subscript on the left while the mass number of the atomic mass is placed as a superscript on the same left.
Looking at the question asked, we have the element symbol in the correct position as Ca, with 42 also in the correct position which is the mass number. The third number which is 20 is thus the atomic number of the element.
Answer:
72.22 g
Explanation:
975 mL Mercury× 13.5 g/mL = 72.22 g
Endo is more in reactants and exo is more in products because in exothermic reactions heat is released
Answer:
60.0mL
Explanation:
For the process of titration , the formula we use is -
M₁V₁ = M₂V₂
Where ,
M₁ = initial concentration
V₁ = initial volume
M₂ = final concentration
V₂ = final volume .
Hence , from the question ,
The given data is ,
M₁ = 0.050 M
V₁ = 30.0mL
M₂ = 0.025 M
V₂ = ?
Now, to determine the unknown quantity , the formula can be applied ,
Hence ,
M₁V₁ = M₂V₂
Putting the respective values ,
0.050 M * 30.0mL = 0.025 M * ?
solving the above equation ,
V₂ = ? = 60.0mL
