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3 years ago

Which of these could be a physical change?

Chemistry

2 answers:

BigorU [14]3 years ago

7 0

Answer:

Explanation:

A physical change is when the form of the matter is just altered. While a chemical change results from a chemical reaction. No reaction is happening during the mixing of the two colors [nothing is boiling, freezing, evaporating, melting ext.] , but after you mix them the end result does look different. That only because we changed the physical properties of it.

(B is not a physical change because the baking powder inside of the cake must under go a reaction that causes the cake to rise. )

olga nikolaevna [1]3 years ago

3 0

Answer:

C. A blue liquid and a yellow liquid mix and make a green liquid.

Explanation:

A physical change is a change in which chemically a substance remains the same but a change in state of matter may occur. It is a reversible change i.e. the substance can be converted into the original state even after the change has occurred. As per option c even if a blue liquid has been mixed with a yellow liquid to produce a green liquid we can still separate both the liquids using a physical method of separation to get the original liquids back.

Other options are wrong because they are examples of chemical change in which the change is irreversible and we can never get the original substance back by any means because a reaction has changed the substance entirely.

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calculate how many milliliters of 0.142 M NaOH are needed to completely neutralize 21.4 mL of 0.294 M H2C4H4O6.

Flura [38]

Answer:

The answer to your question is 88.7 ml

Explanation:

Data

Volume = ?

Concentration of NaOH = 0.142 M

Volume of H₂C₄H₄O₆ = 21.4 ml

Concentration of H₂C₄H₄O₆ = 0.294 M

Balanced chemical reaction

2 NaOH + H₂C₄H₄O₆ ⇒ Na₂C₄H₄O₆ + 2H₂O

1.- Calculate the moles of H₂C₄H₄O₆

Molarity = moles/volume

Solve for moles

moles = Molarity x volume

Substitution

moles = 0.294 x 21.4/1000

Result

moles = 0.0063

2.- Use proportions to calculate the moles of NaOH

2 moles of NaOH ------------------ 1 moles of H₂C₄H₄O₆

x ------------------ 0.0063 moles

x = (0.0063 x 2) / 1

x = 0.0126 moles of NaOH

3.- Calculate the volume of NaOH

Molarity = moles / volume

Solve for volume

Volume = moles/Molarity

Substitution

Volume = 0.0126/0.142

Result

Volume = 0.088 L or 88.7 ml

3 0

3 years ago

18 grams<br> 4 kilograms<br> 8 kilograms

Rina8888 [55]

Answer:

1 18 grams

2 500g

4 960 grams

5 7 kilograms

5 0

3 years ago

What is the molar mass of C4H10

Phantasy [73]

Your answer would be 58.12g/mol ;)

7 0

3 years ago

SeF6 1. Lewis Structure 2. Perspective drawing 3. Number of atoms bonded to central atom 4. Number of non-bonding electron pairs

Anarel [89]

The answer is- $SF_{6}$ is octahedral in electronic and molecular geometry with 6 Fluorine atoms bonded to central atom S.

Lewis structures are the diagrams in which the valence electrons of the atoms of a compound are arranged around the atoms showing the bonding between the atom and the lone pair of electrons existing in the molecule.

Determine the molecular geometry of $SF_{6}$ .

Valence Shell Electron Pair Repulsion theory is commonly known as VSEPR theory and it helps to predict the geometry of molecules.
According to this theory, electrons are arranged around the central atom of the molecule in such a way that there is minimum electrostatic repulsion between these electrons.
Now, calculate the total number of valence electrons in $SF_{6}$ .

$Valence\ electrons\ in\ SF_{6}= Valence\ electrons\ in\ S +\ 6(Valence\ electrons\ in\ F)$

Valence electrons of S = 6

Valence electrons of F = 7

Thus, the valence electrons in $SF_{6}$ are-

$Valence\ number\ of\ electrons\ in\ SF_{6} = (6) + 6(7) = 48\ electrons.$

The Lewis structure of $SF_{6}$ is - (Image attached).
In the structure, the number of atoms bonded to central atom (S) = 6.
Number of non-bonding electron pairs on the central atom = 0 (as all the valence electrons are bonded to F).
Electronic geometry in case of 6 bond pairs is octahedral.
Molecular geometry us also octahedral with bond angles 90°.
Central atom is sp3d2 hybridised.
$SF_{6}$ is a non-polar molecule.

To learn more about Lewis structures visit:

brainly.com/question/12307841?referrer=searchResults

#SPJ4

7 0

1 year ago

A chemist wants to develop a fuel by converting water back to elemental hydrogen and oxygen using coupled ATP hydrolysis to driv

Doss [256]

Answer:

Firstly, we need know that:

Energy of a opposite reaction will equal to = (-) energy of forward reaction.

Therefore,

H2(g) +1/2 O2(g) -------------> H2O (g) ΔfG = -237.13 kJ/mol -----------(1)

ATP + H2O (l) ................. ...........> ADP + Pi ΔG = -31 kJ/mol -----------(2)

The first equation can be written as:

H2O -------------------------> H2 +1/2 O2 ΔG = 237.13 kJ/mol -------------(3)

Equation (3) showed the formation of one mole of H2 gas required energy = 237.13 kJ/mol

Equation (2) showed that one mole of ATP on hydrolysis produces energy = 31.0 kJ/mol

Therefore, to get one mole of H2 gas means:

no of moles of ATP required = energy required for H2 production/energy produced by ATP

= 237.13/31.00

= 7.65 moles

Therefore, to produce one mole H2 gas = 7.65 moles of ATP is required

So in order to produce 3 moles of H2

= x ATP required for one mole

= 3 x 7.649

= 22.947 moles

Therefore, to produce three mole of H2 = 22.9 moles of ATP.

3 0

3 years ago

Read 2 more answers