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Andre45 [30]
3 years ago
15

From where do the placenta and umbilical cord develop?

Chemistry
2 answers:
leva [86]3 years ago
8 0

Answer:

outer cells of the blastocyst

Explanation:

on edg:)

Andreas93 [3]3 years ago
3 0

Answer:

it develops from the womb

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What are weak bonds that allow flexibility in an enzyme
34kurt
Enzymes are characterized to have weak bonds because their tertiary structure could easily bend and break because it will have to adjust to the shape of the substrate. It could be done via induced fitting or lock-and-key theory. These weak bonds are intermolecular forces like the London forces, electrostatic interactions and hydrogen bonding.
7 0
3 years ago
If an equal number of moles of the weak acid HF and the strong base KOH are added to water, is the resulting solution acidic, ba
s344n2d4d5 [400]

Answer:

Being a weak acid and a strong base, where it is diluted in a neutral medium such as water, the basic medium predominates, almost alkaline pH.

Explanation:

The acidity of the solution, being weak, means that its pH is not so low, therefore it will be easier to reach the values of 7 or 7 where alkalinity or basity is indicated.

6 0
3 years ago
You mix 265.0 mL of 1.20 M lead(II) nitrate with 293 mL of 1.55 M potassium iodide. The lead(II) iodide is insoluble. What amoun
slava [35]

Answer:

105 grams PbI₂

Explanation:

Pb(NO₃)₂ + 2KI => 2KNO₃ + PbI₂(s)

moles Pb(NO₃)₂ = 0.265L(1.2M) = 0.318 mole

moles KI = 0.293(1.55M) = 0.454 mole => Limiting Reactant

moles PbI₂ from mole KI in excess Pb(NO₃)₂ = 1/2(0.454 mole) = 0.227 mol PbI₂

grams PbI₂ = 0.227 mol PbI₂ x 461 g/mole = 104.68 g ≈ 105 g PbI₂(s)

7 0
3 years ago
Read 2 more answers
Changes in States of Matter
puteri [66]

Answer:

Melting

Explanation:

From solid to liquid, the change of state happening is the melting process. The kinetic energy of the particles that makes up the solid is increased and it allows the liquid to flow.

  • A solid is a fixed mass with static molecules.
  • When thermal energy is added, the kinetic energy increases.
  • The kinetic energy of the particles increases and they vibrate about their fixed point in solids.
  • This eventually breaks the structure and liquid which begins to flow forms.

This is a melting process.

4 0
3 years ago
Why was it important to let the solution cool down before conducting the titration experiment?
Papessa [141]

Answer:

The pH range, reaction rate, accuracy and solubility are affected by the temperature.

Explanation:

Hello,

Temperature is factor affecting how solutions behave, thus, it could modify the pH range (change in color values) for an indicator in the presence of a base or an acid, since the kinetics behind the change of color is modified maybe decreasing or increasing the aforesaid range. Next, temperature usually increases the reaction rate, that's why the change in color could become faster or out of the proper change range. Then, in titration we use temperature-sensitive glassware which could expand due to high temperatures and subsequently turning out into wrong measurements. Finally, solubility is affected by the temperature, since the molecules are allowed to interact more effectively, that's we must make sure that they're completely dissolved at room temperature while titrating.

Best regards.

6 0
4 years ago
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