Answer:

Explanation:
Hello!
In this case, when we want to balance chemical reactions such as in this case, the idea is to equal to number of atoms of each element at each side of the equation according to the lay of conservation of mass, just as shown below:

Because we have four phosphorous and ten oxygen atoms at each side.
Best regards!
Answer:
A
Explanation:
The answer A is the best answer because it contains the most general characteristic of a chemical change.
Answer:
<em>C</em><em> </em><em>.</em><em> </em><em>the</em><em> </em><em>dramatic</em><em> </em><em>scenery</em><em> </em><em>created</em><em> </em><em>by</em><em> </em><em>volcanic</em><em> </em><em>eruptions</em><em> </em><em>attracts</em><em> </em><em>tourists</em><em>. </em>
Answer: The given statement is true.
Explanation:
Water is a natural resource present in the nature and it is very precious as life without it is impossible.
So, when we unnecessarily use water then it means we are wasting a natural resource that cannot be reproduced again by human beings.
Therefore, more we are able to conserve water more we can protect other human life's and environment also.
If there is shortage of water then its prices will go high and hence we need to pay more for it.
Thus, we can conclude that the statement conserving water can save money while protecting the environment, is true.
The reaction is
CaC₂(s) + 2H₂O (l) -----> Ca(OH)₂ (s) + C₂H₂ (g)
As we have data of gas ethyne (or acetylene), C₂H₂
We can calculate the moles of acetylene and from this we can estimate the mass of calcium carbide taken
the moles of acetylene will be calculated using ideal gas equation
PV =nRT
R = gas constant = 0.0821 Latm/molK
T = 385 K
V = volume = 550 L
P = Pressure = 1.25 atm
n = moles = ?
n = PV /RT = 1.25 X 550 / 0.0821 X 385 = 21.75 mol
As per balanced equation these moles of acetylene will be obtained from same moles of calcium carbide
moles of calcium carbide = 21.75mol
molar mass of CaC₂ = 40 + 24 = 64
mass of CaC₂ = moles X molar mass = 21.75 X 64 = 1392g