When KOH and Cu(NO3)2 are mixed it yields copper(II) hydroxide and potassium nitrate. The balanced reaction is:
Cu(No3)2(aq) + 2 KOH(aq)<span> = Cu(OH)2(s) + 2 KNo3(aq)
</span>
As we can see from the equation a solid is formed therefore a
precipitate is formed which is the copper (II) hydroxide which has a blue to
purple appearance. This can be observed since copper
(II) hydroxide has a low
solubility in aqueous solution.
Answer:
B. Triazine-resistant weeds were more likely to survive and reproduce
Explanation:
According to darwin's theory of evolution, variation is already present in some members of a population and this variation lets them survive in the adverse condition and those who do not have that variation which helps in survival are lost with time.
So as before using triazine herbicide the major population of the weed were not resistant to this herbicide so in the first few years the nonresistant weeds were lost and only resistant weed which was very less in number survived.
So after several years these resistant weeds reproduced and transferred their gene to their offsprings and became predominant in the field. Therefore the correct answer is B.
B. Oxygen. Hope this helps.
![mol = \frac{mass}{molar mass}](https://tex.z-dn.net/?f=mol%20%3D%20%20%5Cfrac%7Bmass%7D%7Bmolar%20mass%7D%20)
<span>
</span>∴
![mol of ZnCl_{2} = \frac{2.00 g}{[(65)+(35.5 * 2)g/mol}](https://tex.z-dn.net/?f=mol%20of%20ZnCl_%7B2%7D%20%3D%20%20%5Cfrac%7B2.00%20g%7D%7B%5B%2865%29%2B%2835.5%20%2A%202%29g%2Fmol%7D%20)
=
![\frac{2.00 g}{136 g/mol}](https://tex.z-dn.net/?f=%20%5Cfrac%7B2.00%20g%7D%7B136%20g%2Fmol%7D%20)
= 0.0147 mol
![Moles of Na_{2}Zn(OH)_{4} :](https://tex.z-dn.net/?f=Moles%20of%20Na_%7B2%7DZn%28OH%29_%7B4%7D%20%20%3A)
![ratio of ZnCl_{2} : Na_{2}Zn(OH)_{4}](https://tex.z-dn.net/?f=ratio%20of%20ZnCl_%7B2%7D%20%20%3A%20%20Na_%7B2%7DZn%28OH%29_%7B4%7D%20%20)
1 : 1
∴
![Moles of Na_{2}Zn(OH)_{4}](https://tex.z-dn.net/?f=Moles%20of%20Na_%7B2%7DZn%28OH%29_%7B4%7D%20%3Cspan%3E)
= 0.0147 mol
Mass = Molar Mass * Mol
∴
![Mass of Na_{2}Zn(OH)_{4}](https://tex.z-dn.net/?f=Mass%20of%20Na_%7B2%7DZn%28OH%29_%7B4%7D%20%3Cspan%3E)
= [(23 * 2)+(65)+(16 * 4) + (1*4)] g/mol * 0.0147 mol
= 179 g/mol * 0.0147 mol
=
2.63 g
Answer:
the answer is carrying oxygenated blood and nutrients to cells