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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 atom has 5 neutrons 4 protons and 2 electrons
Vilka [71]
<span>the atom that has these characteritics is called beryllium nucleus</span>
6 0
2 years ago
4. How can acids and bases behave in terms of electrolytes/reactivity?
icang [17]

Answer:

Strong acids are strong electrolytes. Such acids ionize completely.

Weak acids and bases are weak electrolytes. Such bases and acids ionize only to a small extent.

Explanation:

Electrolytes are the substances that produce ions when they are dissolved in water. Electrolytes can be categorized as bases, acids, and salts.

Strong acids are strong electrolytes. Such acids ionize completely.

Weak acids and bases are weak electrolytes. Such bases and acids ionize only to a small extent.

7 0
2 years ago
A 25.0-mL sample of 0.150 M hydrazoic acid, HN3, is titrated with a 0.150 M NaOH solution. What is the pH after 13.3 mL of base
tamaranim1 [39]

Answer:

pH ≅ 4.80

Explanation:

Given that:

the volume of HN₃ = 25 mL = 0.025 L

Molarity of HN₃ = 0.150 M

number of moles of HN₃ = 0.025 × 0.150

number of moles of HN₃ =  0.00375  mol

Molarity of NaOH = 0.150 M

the volume of NaOH = 13.3 mL = 0.0133

number of moles of NaOH = 0.0133× 0.150

number of moles of NaOH = 0.001995 mol

The chemical equation for the reaction of this process can be written as:

HN_3 + OH- ---> N^-_{3} + H_2O

1 mole of hydrazoic acid react with 1 mole of hydroxide to give nitride ion and water

thus the new number of moles of HN₃ = 0.00375 - 0.001995 = 0.001755 mol

Total volume used in the reaction =  0.025 +  0.0133 = 0.0383  L

Concentration of HN_3 = \dfrac{0.001755}{0.0383} = 0.0458 M

Concentration of N^{-}_3 = \dfrac{ 0.001995 }{0.0383} = 0.0521 M

GIven that :

Ka = 1.9 x 10^{-5}

Thus; it's pKa = 4.72

pH =4.72 +  log(\dfrac{ \ 0.0521}{0.0458})

pH =4.72 + log(1.1376)

pH =4.72 + 0.05598

pH =4.77598

pH ≅ 4.80

3 0
3 years ago
An orbital of an atom is defined as the most probable location of(1) an electron (2) a neutron (3) a positron (4) a proton
Montano1993 [528]

Answer: option (1) an electron.


Justification:


1) The plum pudding model of the atom conceived by the scientist J.J. Thompson, described the atom as a solid sphere positively charged with the electrons (particles negatively charged) embedded.


2) The next model of the atom, developed by the scientist Ernest Rutherford, depicted the atom a mostly empty space with a small dense positively charged nucleous and the electrons surrounding it.


3) Then, Niels Bhor came out with the model of electrons in fixed orbits around the nucleous, just like the planets orbit the Sun. So, the path followed by the electrons were orbits.


4) The quantum model of the atom did not place the electrons in fixed orbits around the nucleous but in regions around the nucleous. Those regions were named orbitals. And they are regions were it is most probable to find the electron, since it is not possible to tell the exact position of an electron.


As per this model, the electron has a wave function associated. The scientist Schrodinger developed the wave equation which predicts the location of the electron as a probability.


The orbitals are those regions were it is most likely to find the electron. Those regions are thought as clouds of electrons.

5 0
3 years ago
Read 2 more answers
You plug in an extension cord and have to be very careful around the electrical outlet. However, you can handle the extension co
evablogger [386]
Because the cord is wrapped in rubber or plastic and they are not good conductors
4 0
3 years ago
Read 2 more answers
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