Answer:
⇒ 
Explanation:
In balancing a chemical equation we make sure the number of atoms of each element on the reactant side of the equation equals that on the product side
⇒ 
The equation above represents an unbalanced equation of the reaction of aqueous ammonium chloride with aqueous barium nitrate .we can balance this equation by adding the right coefficients to reactants and product.
⇒ 
Answer: 4.18925 kJ heat is needed to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.
Explanation:
Temperature of Solid
Melting temperature of Solid 
Temperature of liquid 
Specific heats of solid ethanol = 0.97 J/gK
Specific heats of liquid ethanol = 2.3 J/gK
Heat required to melt the the 25 g solid
at 159 K
= 159 K - 138 K = 21 K

Heat required to melt and raise the temperature of
upto 223 K
= 223 K - 159 K = 64 K

Total heat to convert solid ethanol to liquid ethanol at given temperature :
(1kJ=1000J)
Hence, 4.18925 kJ of heat will be required to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.
Answer : The technology that can make coal a cleaner fuel is to use lower quality of coal with high sulfur content.
Explanation : Using lower quality of coal with high amount of sulfur in it can make coal a cleaner fuel because of high amount of sulfur it will have better combustion.
Explanation:
As it is given that solubility of water in diethyl ether is 1.468 %. This means that in 100 ml saturated solution water present is 1.468 ml.
Hence, amount of diethyl ether present will be calculated as follows.
(100ml - 1.468 ml)
= 98.532 ml
So, it means that 98.532 ml of diethyl ether can dissolve 1.468 ml of water.
Hence, 23 ml of diethyl ether can dissolve the amount of water will be calculated as follows.
Amount of water = 
= 0.3427 ml
Now, when magnesium dissolves in water then the reaction will be as follows.

Molar mass of Mg = 24.305 g
Molar mass of
= 18 g
Therefore, amount of magnesium present in 0.3427 ml of water is calculated as follows.
Amount of Mg =
= 0.462 g
Answer: The correct option is B.
Explanation: To describe the motion of an object, we use the equations of motion.



From the above equations, we require position, speed and direction through which we an calculate the displacement, velocity and acceleration.
To calculate the complete motion of an object, we require all the three factors.
Hence, the correct option is B.