STP condition mean we have P=1 atm. T=273K. R=ideal gas constant, but make sure you use the one that has the same units of pressure, temperature that you are using. In this case R=0.0821 L*atm K^-1mol^1. You are provided with n=2.1 moles.
V=nRTP
Input your values and solve.
Answer: <em>Acceleration of the ball in the given system is 5 meter per Second Square</em>
<em>The laws of motion are used to determine various aspects of an object in motion</em>.
Explanation:
Applying the first law of motion to calculate acceleration; if formula used in first law is given as 
Here we have a final velocity as 40 meter per second and initial velocity as 20 meter per second and time span is given as 2 second applying the given values in the given equation and finding the value of a
Accuracy is when you hit as close as to the target as you can and precision is when you are on point
Empirical formula is calculated as follows
calculate the moles of each element, that is % composition/ molar mass
molar masses ( Si= 28.09g/mol , Cl= 35.5 g/mol, I=126.9 g/mol)
moles of silicon = 7.962/28.09g/mol= 0.283 moles
moles of chlorine = 20.10 / 35.5g/mol = 0.566 moles
moles of iodine= 71.94 / 126.9 g/mol= 0.567 moles
divide each mole with smallest mole (0.283)
that is silicon = 0.283/0.283= 1 mole
chlorine = 0.566/0.283= 2 mole
Iodine= o.567/0.283= 2 moles
empirical formula is therefore= SiCl2I2
Normal rainwater has a pH of 5.6<span> (slightly acidic)</span>