The balanced chemical equation for reaction of 
and 
is as follows:
From the balanced chemical equation, 2 mol of reacts with 1 mol of 
.
First calculating number of moles of as follows:
On rearranging,
Here, M is molarity and V is volume. The molarity of is given 0.274 M or mol/L and volume 155 mL, putting the values,
Since, 1 mol of reacts with 2 mol of thus, number of moles of will be 
.
Now, molarity of is given 0.305 M or mol/L thus, volume can be calculated as follows:
Therefore, volume of is 278.5 mL.
Answer:
The true statement is:
They are formed when atoms of different elements combine.
Explanation:
Compounds are formed when atoms of different elements combine.
Atoms of different elements combine with each other to attain stable electronic configuration.
The atoms can combine with each other in two different ways:
1) By sharing the electrons
2) By exchanging electrons
When they share electrons with each other, they form a covalent bond.
When they exchange electrons, they form an ionic bond.
Answer:
b) 2.0 mol
Explanation:
Given data:
Number of moles of Ca needed = ?
Number of moles of water present = 4.0 mol
Solution:
Chemical equation:
Ca + 2H₂O → Ca(OH)₂ + H₂
now we will compare the moles of Ca and H₂O .
H₂O : Ca
2 : 1
4.0 : 1/2×4.0 = 2.0 mol
Thus, 2 moles of Ca are needed.
