Well you know that you have to balance out the equation to 0. So if I is -1 and Ca is +2 you know that I had to equal to -2. So you can do that by having two of them. So Ca=+2 and I2=-2 so CaI2 would equal 0 meaning that would be the correct answer. Hope that I explained that correct :)
Answer C because it is a balanced equation that shows an equal amount of hydrogen atoms on both sides of the equation as well as an equal amount of oxygen on both sides. No atoms are lost or destroyed in this equation
Answer:
Error percentage = 1.326% , 1.35% , 5.37%
density = mass / volume
For first sample:
density = 37.22/11.5 = 3.2365 g/ml
then percentage error = 100% - (3.2365/3.28 ) * 100 = 1.326%
For second sample:
density = 37.21/11.5 = 3.2356 g/ml
then percentage error = 100% - ( 3.2356 / 3.28 ) *100 = 1.35%
For third sample:
density = 37.25/12 = 3.104 g/ml
then percentage error = 100% - ( 3.104 / 3.28 ) *100 = 5.37%
No, It can't be chemical because it has something to do with being mechanical, an example of a chemical change would be some thing like metal rusting or wood turning to ash after being burned.