Answer:
Weigh 4.5 grams of sodium hydroxide and add it to the dry volumetric flask of 450 mL followed by small amount of water to dissolve all the NaOH .After this add the water upto tye mark of 450 mL.
Explanation:
Molarity of the solution is the moles of compound in 1 Liter solutions.

Mass of NaOH = x
Molar mass of NaOH = 40 g/mol
Volume of the NaOH solution = 450 mL =- 0.450 L ( 1 ml = 0.450 L)
Molarity of the solution of NaOH = 0.250 M


Solving for x:
x = 4.5 g
Weigh 4.5 grams of sodium hydroxide and add it to the dry volumetric flask of 450 mL followed by small amount of water to dissolve all the NaOH .After this add the water upto tye mark of 450 mL.
<span>
</span><span> average reaction rate </span><span>= change in concentration / change in time
by putting values we have
= (1.00M - 0.987M) / (4.00s - 0.00s)
= 3.25x10^-3 mol/Lsec
this is our conclusion
hope this helps</span>
Answer:
Mixtures can be either homogeneous or heterogeneous. A mixture in which its constituents are distributed uniformly is called homogeneous mixture, such as salt in water. A mixture in which its constituents are not distributed uniformly is called heterogeneous mixture, such as sand in water.
<u>Answer:</u> The Henry's law constant for oxygen gas in water is 
<u>Explanation:</u>
To calculate the molar solubility, we use the equation given by Henry's law, which is:

where,
= Henry's constant = ?
= solubility of oxygen gas = 
= partial pressure of oxygen gas = 2.1 atm
Putting values in above equation, we get:

Hence, the Henry's law constant for oxygen gas in water is 
Answer: The ratio of the number of oxygen molecules to the number of nitrogen molecules in these flasks is 1: 1
Explanation:
According to avogadro's law, equal volumes of all gases at same temperature and pressure have equal number of moles.
According to avogadro's law, 1 mole of every substance contains avogadro's number
of particles.
Thus as oxygen and nitrogen are at same temperature and pressure and are in equal volume flasks , they have same number of moles and thus have same number of molecules.
The ratio of the number of oxygen molecules to the number of nitrogen molecules in these flasks is 1: 1