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3 years ago

Which process is a chemical change

2 answers:

4 0

Burning a match, In chemistry, there are two basic types of change, these are physical and chemical change. In physical change, no new material is formed and the process is reversible while in chemical change new materials are formed and the process is irreversible

zimovet [89]3 years ago

3 0

Answer: A process that is a chemical change is Chemical reactions involve combining different substances. They produces a new substances with new and different physical and chemical properties.

Explanation:

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The Henry's law constant (kH) for O2 in water at 20°C is 1.28e-3 mol/l atm. How many grams of O2 will dissolve in 3.5 L of H2O t

Sophie [7]

Answer : The mass of $O_2$ dissolved will be, 0.2365 grams

Explanation :

First we have to calculate the concentration of $O_2$ .

As we know that,

$C_{O_2}=k_H\times p_{O_2}$

where,

$C_{O_2}$ = concentration of $O_2$ = ?

$p_{O_2}$ = partial pressure of $O_2$ = 1.65 atm

$k_H$ = Henry's law constant = $1.28\times 10^{-3}mole/L.atm$

Now put all the given values in the above formula, we get:

$C_{O_2}=(1.28\times 10^{-3}mole/L.atm)\times (1.65atm)$

$C_{O_2}=2.112\times 10^{-3}mole/L$

The concentration of $O_2$ = $2.112\times 10^{-3}mole/L$

Now we have to calculate the moles of $O_2$

$\text{Moles of }O_2=\text{Concentration of }O_2\times \text{volume of solution}$

$\text{Moles of }O_2=(2.112\times 10^{-3}mole/L)\times (3.5L)=7.392\times 10^{-3}mole$

Now we have to calculate the mass of $O_2$

$\text{Mass of }O_2=\text{Moles of }O_2\times \text{Molar mass of }O_2$

$\text{Mass of }O_2=(7.392\times 10^{-3}mole)\times (32g/mole)=0.2365g$

Therefore, the mass of $O_2$ dissolved will be, 0.2365 grams

4 0

3 years ago

A student determines that a 1.5 g mixture of CaCO3(s) and

zysi [14]

We are given:

Mass of the mixture = 1.5 grams

Number of Moles of NaHCO₃ = 0.01 mole

Mass of 0.01 moles of NaHCO₃:

Mass = number of moles * Molar mass

Mass = 0.01 * 84

Mass = 0.84 grams

Mass% of Na in NaHCO₃:

Molar mass of NaHCO₃ = 84 grams/mol

Molar mass of Na = 23 grams / mol

Mass% = (Molar mass of Na / Molar mass of NaHCO₃) * 100

Mass% = (23/84) * 100

Mass% = 27%

Mass of Na in 0.01 moles:

Since the Mass% of Na is 27% and the total mass is 0.84 grams

So, we can say that 27% of 0.84 is the mass of Na

Mass of Na = 0.84 * 0.27

Mass of Na = 0.23 grams

Mass% of Na in the mixture:

Total mass of the mixture = 1.5 grams

Mass of Na in the mixture = 0.23 grams

Mass% of of Na in the Mixture = (Mass of Na / Mass of Mixture) * 100

Mass% of Na = (0.23 / 1.5) * 100

Mass% of Na = 15.3%

Therefore, we have 15.3% Na in the given mixture by mass

7 0

3 years ago

Is Cytoplasm found in animal cells,plant cells or in both?

nataly862011 [7]

Answer:

cytoplasm is found in both plant and animal cell.

3 0

3 years ago

Read 2 more answers

Between Lab Period 1 and Lab Period 2, design a separation scheme for all 4 cations. Use the results of your preliminary tests a

fiasKO [112]

Answer:

SEPARATION SCHEME FOR CATIONS

GIVEN CATIONS : $Ag^{+} \ , Fe^{3+} , Cu^{2+}, Ni^{2+}$

Step 1: Add $6mol/dm^3$ of $HCl$ to the mixture solution

Result : This would cause a precipitate of $AgCl$ to be formed

Reaction : $Ag^{+} _{(aq)} + Cl^{-} _{(aq)} ---------> AgCl(ppt)$

Step 2 : Next is to remove the precipitate and add $H_2S$ to the remaining

solution in the presence of $0.2 \ mol/dm^3$ of HCl

Result : This would cause a precipitate of $CuS$ to be formed

Reaction : $Cu^{2+}_{(aq)} + S^{2-}_{(aq)} ------> Cu_2S(ppt)$

Step 3: Next remove the precipitate then add $6 \ mol/dm^3$ of aqueous

$NH_3 (NH_3 \cdot H_2 O)$ , process the solution in a centrifuge,when the

process is done then sort out the precipitate from the solution

Now this precipitate is $Fe(OH)_3$ and the remaining solution

contains $(Ni (NH_3)_6)$

Next take out the precipitate to a different beaker and add HCl

to it this will dissolve it, then add a drop of $NH_4SCN$ this will

form a precipitate $Fe(SCN)_{6}^{3-}$ which will have the color of

blood indicating the presence of $Fe^{3+}$

Reaction : $F^{3+}_{(aq)} + 30H^-_{(aq)} --------->Fe(OH)_3_{(aq)}$

$Fe (OH)_{(s)} _3 + 3H^{+}_{aq} -------> Fe^{3+}_{aq} + 3H_2O_{(l)}$

$Fe^{3+} + 6SCN^{-} -----> Fe(SCN)_6 ^{3-}$

Now the remaining mixture contains $Ni^{2+}$

Explanation:

6 0

3 years ago

The two reactions illustrated in the diagrams below often occur when a foreign substance enters the body.

zheka24 [161]

The specific proteins produced by cell B in response to the foreign substance are antibodies.

<h3>What are antibodies?</h3>

Antibodies are specific proteins produced by the immune cells of the body in response to a foreign substance called antigen which produces the immune response.

Antibodies are released by immune cells such as B cells.

The antibodies bind to antigen and tag them for destruction by phagocytes.

Therefore, cell B will produce antibodies.

Learn more about antibodies at: brainly.com/question/15382995

7 0

2 years ago

Which process is a chemical change​

Which process is a chemical change