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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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A scientist claimed that he radiocarbon dated a fossilized skull of a dinosaur and found it to be about 63 million years old. Do

Elodia [21]

Answer:Since dinosaurs are thought to be over 65 million years old, the news is stunning - and more than some could tolerate. After the AOGS-AGU conference in Singapore, the abstract was removed from the conference website by two chairmen because they could not accept the findings. Unwilling to challenge the data openly, they erased the report from public view without a word to the authors. When the authors inquired, they received this letter:

Explanation:

i do not own my copyrights

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2 years ago

A 25.00-mL aliquot of a nitric acid solution of unknown concentration is pipetted into a 125-mL Erlenmeyer flask and 2 drops of

Semenov [28]

Answer:

0.0611M of HNO3

Explanation:

<em>The concentration of the NaOH solution must be 0.1198M</em>

<em />

The reaction of NaOH with HNO3 is:

NaOH + HNO3 → NaNO3 + H2O

<em>1 mole of NaOH reacts per mole of HNO3.</em>

That means the moles of NaOH used in the titration are equal to moles of HNO3.

<em>Moles HNO3:</em>

12.75mL = 0.01275L * (0.1198mol / L) = 0.0015274 moles NaOH = Moles HNO3.

In 25.00mL = 0.025L -The volume of the aliquot-:

0.00153 moles HNO3 / 0.025L =

7 0

3 years ago

A mixture of 14.2 g of H2 and 36.7 g of Ar is placed in a 100.0 L container at

TiliK225 [7]

a) The total pressure of the system is 1.79 atm

b) The mole fraction and partial pressure of hydrogen is 0.89 and 1.59 atm respectively

c) The mole fraction and the partial pressure of argon is 0.11 and 0.19 atm.

<h3>What is the total pressure?</h3>

We know tat we can be able to obtain the total pressure in the system by the use of the ideal gas equation. We would have from the equation;

PV = nRT

P = pressure

V = volume

n = Number of moles

R = gas constant

T = temperature

Number of moles of hydrogen = 14.2 g/2g = 7.1 moles

Number of moles of Argon = 36.7 g/40 g/mol

= 0.92 moles

Total number of moles = 7.1 moles + 0.92 moles = 8.02 moles

Then;

P = nRT/V

P = 8.02 * 0.082 * 273/100

P = 1.79 atm

Mole fraction of hydrogen = 7.1/8.02 = 0.89

Partial pressure of hydrogen = 0.89 * 1.79 atm

= 1.59 atm

Mole fraction of argon = 0.92 / 8.02

= 0.11

Partial pressure of argon = 0.11 * 1.79 atm

= 0.19 atm

Learn more about partial pressure:brainly.com/question/13199169

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3 0

1 year ago

Phosphine, an extremely poisonous and highly reactive gas, will react with oxygen to form tetraphosphorus decoxide and water, as

erica [24]

<u>Answer:</u> The amount of $P_4O_{10}$ formed is 469.8 grams.

<u>Explanation:</u>

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ ......(1)

Given mass of phosphine = 225 g

Molar mass of phosphine = 34 g/mol

Putting values in equation 1, we get:

$\text{Moles of phosphine}=\frac{225g}{34g/mol}=6.62mol$

The given chemical reaction follows:

$4PH_3(g)+8O_2(g)\rightarrow P_4O_{10}(s)+6H_2O(g)$

Assuming that oxygen gas is present in excess, it is considered as an excess reagent.

Phosphine is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

4 moles of phosphine produces 1 mole of $P_4O_{10}$

So, 6.62 moles of phosphine will produce = $\frac{1}{4}\times 6.62=1.655mol$ of $P_4O_{10}$

Now, calculating the mass of $P_4O_{10}$ by using equation 1:

Molar mass of $P_4O_{10}$ = 283.9 g/mol

Moles of $P_4O_{10}$ = 1.655 moles

Putting values in equation 1, we get:

$1.655mol=\frac{\text{Mass of }P_4O_{10}}{283.9g/mol}\\\\\text{Mass of }P_4O_{10}=(1.655mol\times 283.9g/mol)=469.8g$

Hence, the amount of $P_4O_{10}$ formed is 469.8 grams.

8 0

2 years ago

What molecules have 5 carbon atoms and 12 hydrogen atoms

goldfiish [28.3K]

ANSWER

THE PENTANES

EXPLANATION

he word for5 in Greek is PENT like the 5 sided and 5 angled building in Wachington the PENTagon.

SO C5H12 IS PENTAND BECAUSE IT HAS NO DOUBLE BONDAS IT IS AN ALKANE

SO SO C5H12 IS PENT-ANE PENTANE AND THERE ARE MULTIPLE FORMS OF IT

4 0

2 years ago