Answer:
205 K (to 3 significant figures)
Explanation:
Assuming that 4 moles of the gas behaves like an ideal gas and obey the kinetic molecular theory.
Let's apply the ideal gas law, pV= nRT.
Here p denotes the pressure of the gas, V is for volume, n is the number of moles of the gas, R is the universal gas constant and T is the temperature.
Substitute the given information into the equation:
5.6 atm ×12 L= 4 mol ×R ×T
Since pressure is in atm and volume is in L, we can use R= 0.08206 L atm K⁻¹ mol⁻¹.
5.6 atm ×12 L= 4 mol ×0.08206 L atm K⁻¹ mol⁻¹ ×T
T= 67.2 ÷0.32824
T= 204.73 (5 s.f.)
T= 205 K (3 s.f.)
0.15*240=36 ml of alcohol in <span>240 ml of a 15% alcohol mixture
0.4x = </span>ml of alcohol in x ml of a 40% alcohol mixture
0.2(x+240)= ml of alcohol in (x+240) ml of a 20% alcohol mixture
0.15*240 + 0.4x = 0.2(x+240)
36+0.4x=0.2x+48
0.2x = 12
x=12/0.2=120/6=20 ml of a 40% alcohol mixture
Answer:
C
Explanation:
A physical change is one in which no new substance is formed. The moistening of food by saliva is purely a physical change because no new substance is formed in the process.
A chemical change leads to the formation of a new substance. The action of the enzyme converts starch into sugar which means that a new substance is formed. This is a chemical change.
Answer:
The answer is 20 % V/V
Explanation:
We use this formula for calculate the %V/V:
%V/V= (ml solute/ml solution) x 100= (75ml/375 ml)x 100 = 20 % V/V
<em>The% V / V represents the amount of ml of solute dissolved in 100 ml of solution</em>
Answer:
There are 3600 pages to 2 significant figures
Explanation:
Working only with the information given, we have that there are 23 books each with about 31 chapters.
This means that if 1 book has 31 chapter, the 23 science books will have
31 X 23 chapters =713 chapters in total.
If each chapter contains 5 pages, for the 713 chapters we will have a total of 713 X 5 pages = 3565 pages.
Rounding off the answer to 2 significant figures , we are looking to have only two non-zero figures in our answer. To do this, we count two numbers from the left. This will be numbers 3 and 5.
Next, we check the net number after 5 to see if it is greater than 5 if it is, we will have to add the number (1 ) to the 5. This shows that we are approximating upwards, to account for the fact that that number has passed the middle point.
After this, we change the remaining two numbers (6 and 5) to zeroes.
This will give us 3600 pages.
