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3 years ago

HELP FAST! 35 POINTS! Why is flammability a chemical property?

1 answer:

8 0

Flammmability is a chemical change because it changes the composition of the object. the product is very different from the rectant.

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We dissolve 93 grams of sodium sulfate (Na2SO4) in 20 grams of water. What is the percent by mass of sodium sulfate in this solu

dlinn [17]

It should be for the total solution of 93 plus 20 grams which is 113 grams so 93 divided by 113 grams comes to 82.3% sodium sulfate and this can be checked by multiplying 113 grams by 0.823 which results in 93 grams of sodium sulphate.

4 0

3 years ago

If the ph of a solution is decreased from ph 8 to ph 6 it means that the

saw5 [17]

Explanation:

Relation between pH and concentration of hydrogen ions is as follows.

pH = $-log [H^{+}]$

So, it means that an increase in the value of pH will show that there occurs a decrease in concentration of hydrogen ions.

Therefore, the solution becomes basic in nature.

On the other hand, a decrease in the value of pH will show that there occurs an increase in the concentration of hydrogen ions.

Therefore, the solution becomes more acidic in nature.

Hence, if the pH of a solution is decreased from pH 8 to pH 6 it means that the concentration of hydrogen ions has increased in the solution.

5 0

3 years ago

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The amount ofcalcium present in milk can be determined by adding oxalate to asample and measuring the massof calcium oxalate pre

Sauron [17]

<u>Answer:</u> The mass percent of calcium in milk is 0.107 %

<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 calcium oxalate = 0.429 g

Molar mass of calcium oxalate = 128.1 g/mol

Putting values in equation 1, we get:

$\text{Moles of calcium oxalate}=\frac{0.429g}{128.1g/mol}=0.0033mol$

The given chemical equation follows:

$Na_2C_2O_4(aq.)+Ca^{2+}(aq.)\rightarrow CaC_2O_4(s)+2Na^+(aq.)$

Sodium oxalate is present in excess. So, it is considered as an excess reagent. And, calcium ion is a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

1 mole of calcium oxalate is produced from 1 mole of calcium ion

So, 0.0033 moles of calcium oxalate is produced from = $\frac{1}{1}\times 0.0033=0.0033mol$ of calcium ions

Now, calculating the mass of calcium ions by using equation 1, we get:

Moles of calcium ions = 0.0033 moles

Molar mass of calcium ions = 40 g/mol

Putting values in equation 1, we get:

$0.0033mol=\frac{\text{Mass of calcium ions}}{40g/mol}\\\\\text{Mass of calcium ions}=(0.0033mol\times 40g/mol)=0.132g$

To calculate the mass percentage of calcium ions in milk, we use the equation:

$\text{Mass percent of calcium ions}=\frac{\text{Mass of calcium ions}}{\text{Mass of milk}}\times 100$

Mass of milk = 125 g

Mass of calcium ions = 0.132 g

Putting values in above equation, we get:

$\text{Mass percent of calcium ions}=\frac{0.132g}{125g}\times 100=0.107\%$

Hence, the mass percent of calcium in milk is 0.107 %

7 0

3 years ago

92dm3 of a gas dissolved in a solvent. How many moles is this?

Paul [167]

Assuming its at r. t.p and pressure
no. of moles = 96/24=4moles
altho some books will say that its 23.7dm3/mole but that doesnt really matter because its the process that matters

5 0

3 years ago

The measurable properties of a substance, such as vapor pressure and surface tension, occur due to the strength of

SpyIntel [72]

Properties of a substance such as vapor pressure and surface tension depend on electrical forces between particles, as given by Coulomb's law.

The vapor pressure refers to how easily a liquid converts to gas while surface tension is the force that makes a liquid surface act as a stretched elastic skin.

Both vapor pressure and surface tension has a lot to do with the degree of polarity in a molecule. Usually, polar molecules have a low vapor pressure and high surface tension due to a high electrical forces between particles, as given by Coulomb's law.

Learn more: brainly.com/question/13440572

8 0

3 years ago

Read 2 more answers