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3 years ago

What does the law of conservation of energy state?

Chemistry

1 answer:

Anarel [89]3 years ago

4 0

Answer:

it states that the total mass of the products are the same as the total mass of the reactants in a chemical reaction.

Explanation:

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A standard solution of FeSCN2+ is prepared by combining 9.0 mL of 0.20 M Fe(NO3)3 with 1.0 mL of 0.0020 M KSCN . The standard so

Xelga [282]

Answer : The equilibrium concentration of $SCN^-$ in the trial solution is $4.58\times 10^{-8}M$

Explanation :

First we have to calculate the initial moles of $Fe^{3+}$ and $SCN^-$ .

$\text{Moles of }Fe^{3+}=\text{Concentration of }Fe^{3+}\times \text{Volume of solution}$

$\text{Moles of }Fe^{3+}=0.20M\times 9.0mL=1.8mmol$

and,

$\text{Moles of }SCN^-=\text{Concentration of }SCN^-\times \text{Volume of solution}$

$\text{Moles of }SCN^-=0.0020M\times 1.0mL=0.0020mmol$

The given balanced chemical reaction is,

$Fe^{3+}(aq)+SCN^-(aq)\rightleftharpoons FeSCN^{2+}(aq)$

Since 1 mole of $Fe^{3+}$ reacts with 1 mole of $SCN^-$ to give 1 mole of $FeSCN^{2+}$

The limiting reagent is, $SCN^-$

So, the number of moles of $FeSCN^{2+}$ = 0.0020 mmole

Now we have to calculate the concentration of $FeSCN^{2+}$ .

$\text{Concentration of }FeSCN^{2+}=\frac{0.0020mmol}{9.0mL+1.0mL}=0.00020M$

Using Beer-Lambert's law :

$A=\epsilon \times C\times l$

where,

A = absorbance of solution

C = concentration of solution

l = path length

$\epsilon$ = molar absorptivity coefficient

$\epsilon$ and l are same for stock solution and dilute solution. So,

$\epsilon l=\frac{A}{C}=\frac{0.480}{0.00020M}=2400M^{-1}$

For trial solution:

The equilibrium concentration of $SCN^-$ is,

$[SCN^-]_{eqm}=[SCN^-]_{initial}-[FeSCN^{2+}]$

$[SCN^-]_{initial}$ = 0.00050 M

Now calculate the $[FeSCN^{2+}]$ .

$C=\frac{A}{\epsilon l}=\frac{0.220}{2400M^{-1}}=9.17\times 10^{-5}M$

Now calculate the concentration of $SCN^-$ .

$[SCN^-]_{eqm}=[SCN^-]_{initial}-[FeSCN^{2+}]$

$[SCN^-]_{eqm}=(0.00050M)-(9.17\times 10^{-5}M)$

$[SCN^-]_{eqm}=4.58\times 10^{-8}M$

Therefore, the equilibrium concentration of $SCN^-$ in the trial solution is $4.58\times 10^{-8}M$

5 0

3 years ago

4 NH3 + 6 NO → 5 N2 + 6 H2O How many moles of NH3 are necessary to produce 0.824 mol N2?

GrogVix [38]

4 mol NH₃ → 5 mol N₂
x mol NH₃ → 0.824 mol N₂

x=0.824*4/5=0.6592 mol

6 0

3 years ago

State the guideline you can use to predict the formula of:

Cerrena [4.2K]

We can predict formula of ionic compounds by:

Take a look at where the elements are listed on the periodic table.
The amount of electrons that an element would need to gain or lose in order to resemble an atom of a nearby noble gas is one of the similarities that atoms in the same column as one another (group) tend to display.
Alkali metal group I ions have +1 charges.
Alkaline earth metals (group 2 ions) have a +2 charge.
Nonmetal group 6 ions have a charge of -2.
Halides in group 7 have a -1 charge.
The charges of the transition metals cannot be predicted in a straightforward manner.
Check out a table of charges (valences) to see potential values. The +1, +2, and +3 charges are most frequently employed in beginning and general chemistry courses.
Keep in mind that the positive ion is always stated first when writing an ionic compound's formula.

These are the few guidelines we can use to product formula.

Learn more about ionic compounds here:

brainly.com/question/2687188

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4 0

1 year ago

20 POINTS!!

Alenkinab [10]

Answer:

1. molarity is = 0.1174

2. molarity is = 9.3

3. molarity is =0.009392

Explanation:

Q#1.

mass of sucrose is 14.07g

molar mass of sucrose is 342 3g/mol

so, 14.07x1/342.3 = 0.0411

now the volume is of water is 0.35

so, 0.0411/0.35 = 0.1174

Q#2.

concentration is 4.5

so, 4.5x1/1000= 0.0045

then, 0.0411/0.0045 = 9.13

Q#3.

M1M1=M2M2

molarity of the same sucrose is 0.1174

so, diluted in 40mL

and the volumetric flask is 500mL

so, 0.1174x40/500= 0.009392

8 0

2 years ago

What is one Scientific Law or Scientific Theory that affects our life?

iren [92.7K]

Answer:

Does the Big Bang theory count?

8 0

3 years ago