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3 years ago

STEP 5: LEAD

Chemistry

2 answers:

Pavel [41]3 years ago

4 0

Answer:

the answers are in the pic

Explanation:

BartSMP [9]3 years ago

3 0

Answer:

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what is the approximate ph at the equivalence point of a weak acid-strong base titration if 25 ml of aqueous formic acid require

vivado [14]

Answer:

pH at equivalence point is 8.52

Explanation:

$HCOOH+NaOH\rightarrow HCOO^{-}Na^{+}+H_{2}O$

1 mol of HCOOH reacts with 1 mol of NaOH to produce 1 mol of $HCOO^{-}$

So, moles of NaOH used to reach equivalence point equal to number of moles $HCOO^{-}$ produced at equivalence point.

As density of water is 1g/mL, therefore molarity is equal to molality of an aqueous solution.

So, moles of $HCOO^{-}$ produced = $\frac{29.80\times 0.3567}{1000}moles=0.01063moles$

Total volume of solution at equivalence point = (25+29.80) mL = 54.80 mL

So, at equivalence point concentration of $HCOO^{-}$ = $\frac{0.01063\times 1000}{54.80}M=0.1940M$

At equivalence point, pH depends upon hydrolysis of $HCOO^{-}$ . So, we have to construct an ICE table.

$HCOO^{-}+H_{2}O\rightleftharpoons HCOOH+OH^{-}$

I: 0.1940 0 0

C: -x +x +x

E: 0.1940-x x x

So, $\frac{[HCOOH][OH^{-}]}{[HCOO^{-}]}=K_{b}(HCOO^{-})=\frac{10^{-14}}{Ka(HCOOH)}$

species inside third bracket represent equilibrium concentrations

So, $\frac{x^{2}}{0.1940-x}=5.56\times 10^{-11}$

or, $x^{2}+(5.56\times 10^{-11}\times x)-(1.079\times 10^{-11})=0$

So, $x=\frac{-(5.56\times 10^{-11})+\sqrt{(5.56\times 10^{-11})^{2}+(4\times 1.079\times 10^{-11})}}{2}$

So, $x=3.285\times 10^{-6}M$

So, $pH=14-pOH=14+log[OH^{-}]=14+logx=14+log(3.285\times 10^{-6})=8.52$

5 0

3 years ago

The sum of gravitational potential energy and kinetic

Firlakuza [10]

Answer:

Explanation:

Mechanical energy = Gravitational potential energy + kinetic energy

Time Gravitational potential energy kinetic energy Total ME

0 4 0 4

2 2 2 4

4 0 4 4

6 2 2 4

8 4 0 4

and so on .....

We see that total mechanical energy is always 4 which is constant .

So gravitational and kinetic energy changes cyclically but total mechanical energy is constant .

7 0

3 years ago

Use the dropdown to create a unbalanced diagram with the dog using Applied Force pulling to the right.

Ber [7]

Is there an image with this question

7 0

3 years ago

What is the name of a solution whose concentration of solute is equal to the maximum concentration that

Travka [436]

Answer:

Explanation:

7 0

4 years ago

In this equation, what should be the coefficients of the reactants and products?

Scrat [10]

4 I₂+ 9 O₂ = 2 I₄O₉

Reactants :

I₂ , O₂

Products :

I₄O₉

hope this helps!

7 0

4 years ago