Answer: 2Liters
Explanation:
The expression used will be :
where,
= concentration of first antifreeze= 60%
= concentration of second antifreeze= 10%
= volume of first antifreeze = x L
= volume of second antifreeze = 8 L
= concentration of final antifreeze solution= 20%
= volume of final antifreeze = (x+8) L
Now put all the given values in the above law, we get the volume of antifreeze added
Therefore, the volume of 60% antifreeze solution that must be added is 2L
2 in front of H2. Technically nothing in front of O2 otherwise put a 1 then a 2 in front of H2O
2H20 + 1O2 —— > 2H2O
Given, the density of water is 0.9975 g/ml. Density of water is mass of water per unit volume. Mass of 1 ml of water supposed to be 0.9975 g from density of water. So, mass of 10 ml of water is (0.9975 X 10) g= 9.975 g. From graduated cylinder, mass of 10 ml water is measured to be 9.955 g. So, error for mass of 10 ml water= (9.975-9.955)=0.02 g. Percentage of error for 10 ml water is 
= 0.2. Error in the mass for the 10 ml of water is 0.2 %.
The general process for coal mining and refining is option C.
Coal mining is carried out by two main processes based on the depth, quality, thickness, and structure of coal seam. Based on the depth, coal seam of less than 180ft to the surface is surface mined while coal seems between 180ft.-300ft. are deep mined. The coal mined is transported to a nearby processing plant using a conveyor, train, ship, etc. where it is washed to remove other component like dirt, sulphur, rocks, etc. and afterwards dried.
