1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
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

You might be interested in
Solve the following: Which one is more metallic
Degger [83]

Answer:

aluminum

Explanation:

7 0
3 years ago
) Experimental evidence indicates that the nucleus of an atom
geniusboy [140]

Answer:

A (contains most of the mass of the atom)

Evidence has it that a proton is about 2000 times as massive as an electron.

And there is usually multiple protons and neutrons in the nucleus

From what I just said, you can say that B is wrong

C however is also wrong because protons have a +charge and neutrons are neutrle which means you always have a charge > (greater than) 0

And D is wrong because electrons (which are not in the nucleus) have a neg charge. and protons have a + charge and are in the nucleus

So your answer is A

Hope it helped

Spiky Bob

5 0
3 years ago
A metal ion (X) with a charge of 4+ is attracted to non metal ion (Z) with a charge of 3-. Which of these formulas represents th
Brums [2.3K]

Answer:

D

Explanation:

the charges need to balence out

so finding the LCM which is 12 we find we need 3x's

and 4 zs

so that makes the formula X3Z4 which is D

6 0
2 years ago
Which physical method can be used for obtaining a sample of salt from a sm
lana [24]

The physical method that can be used for obtaining a sample of salt from a small beaker of salt and water would be evaporation.

<h3>Separation of salt and water</h3>

A mixture of salt and water can be separated by a method known as evaporation. This is based on the assumption that the salt in question is a water-soluble salt.

In order to separate the salt/water mixture:

  • Place the mixture in a suitable evaporating dish
  • Boil the mixture until all the water evaporates.
  • The remaining residue would be the salt

Care should be taken not to overheat the residue in order to avoid melting. Evaporation is generally used to separate a mixture of water and soluble salt. If the salt is insoluble, filtration using a suitable filter paper will filter off the salt while the water is collected as the filtrate.

More on evaporation can be found here: brainly.com/question/1097783

#SPJ1

Which physical method can be used for obtaining a sample of salt from a small beaker of salt water?

6 0
1 year ago
Given these reactions, X ( s ) + 1 2 O 2 ( g ) ⟶ XO ( s ) Δ H = − 668.5 k J / m o l XCO 3 ( s ) ⟶ XO ( s ) + CO 2 ( g ) Δ H = +
qwelly [4]

<u>Answer:</u> The \Delta H^o_{rxn} for the reaction is -1052.8 kJ.

<u>Explanation:</u>

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The given chemical reaction follows:

X(s)+\frac{1}{2}O_2(g)+CO_2(g)\rightarrow XCO_3(s)      \Delta H^o_{rxn}=?

The intermediate balanced chemical reaction are:

(1) X(s)+\frac{1}{2}O_2(g)\rightarrow XO(s)    \Delta H_1=-668.5kJ

(2) XCO_3(s)\rightarrow XO(s)+CO_2     \Delta H_2=+384.3kJ

The expression for enthalpy of the reaction follows:

\Delta H^o_{rxn}=[1\times \Delta H_1]+[1\times (-\Delta H_2)]

Putting values in above equation, we get:

\Delta H^o_{rxn}=[(1\times (-668.5))+(1\times (-384.3))=-1052.8kJ

Hence, the \Delta H^o_{rxn} for the reaction is -1052.8 kJ.

7 0
3 years ago
Other questions:
  • Freon−12 (CF2Cl2), widely used as a refrigerant and aerosol propellant, is a dangerous air pollutant. In the troposphere, it tra
    9·1 answer
  • Which substance can be decomposed by a chemical change?<br> (1) Co (3) Cr(2) CO (4) Cu
    10·1 answer
  • Why do light-fur mice survive less often on dark rocks, compared to dark- figure mice?
    13·1 answer
  • What type of molecule is shown below?
    7·1 answer
  • Plzzz someone help me last question
    8·1 answer
  • How do you calculate the volume of a cube? A. with a graduated cylindar in mL? B. with a triple beam balance in g? C. with a bea
    9·1 answer
  • 7th grade science , please don’t get the answer from the internet :(
    10·1 answer
  • The diagram below shows the different phase transitions that occur in matter.
    12·2 answers
  • What is an empirical formula
    12·1 answer
  • Competitive inhibition occurs when a
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!