When you doing a titration, you need to use an indicator to confirm whether the reaction is completed. When the indicator has the color change and will not change back in one minute, the reaction is finished and you don't need to add more.
Remember that:
number of moles = mass/molar mass
First, we get the molar mass of the nitrogen gas molecule:
It is known the the nitrogen gas is composed of two nitrogen atoms, each with molar mass 14 gm (from the periodic table)
Therefore, molar mass of nitrogen gas = 14 x 2 = 28 gm
Second we calculate the mass of the precipitate:
we have number of moles = 0.03 moles (given)
and molar mass = 28 gm (calculated)
Using the equation mentioned before,
mass = number of moles x molar mass = 0.03 x 28 = 0.84 gm
Answer:
0.55mL of carbon tetrachloride
Explanation:
CH4(g) + 2Cl2(g) -------> CCl4(g) + 2H2(g)
From the balanced reaction equation
44800mL of chlorine produces 22400 ml of carbon tetrachloride
If 1.1mL of chlorine were consumed, volume of carbon tetrachloride= 1.1×22400/44800
=0.55mL of carbon tetrachloride
Note: 1 mole of a gas occupies 22.4L volume or 22400mL
Answer:
d. white blood cells
Explanation:
It is the white blood cells that have the least tendency to cross the blood- brain barrier.
Blood- brain barrier is psychological barrier and restricts substances that circulate into the blood from crossing over the central nervous system.
Water, glucose as well as sodium ions can easily cross the barrier. As these are good for body supply energy to the brain.
