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3 years ago

15

The outline of a partial periodic table is shown.

2 answers:

Irina-Kira [14]3 years ago

7 0

I think is section 3

vova2212 [387]3 years ago

4 0

Answer:

I think section #3

Explanation:

When i was in science class in my memory it was always in that area

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What happens to crayons when heated?

Olin [163]

they become liquified

3 0

3 years ago

If a 95.27 mL sample of acetic acid (HC2H3O2) is titrated to the equivalence point with 79.06 mL of 0.113 M KOH, what is the pH

KATRIN_1 [288]

Answer:

8.73

Explanation:

The concentration of acetic acid can be determined as follows:

$M_1V_1 = M_2V_2\\(KOH) = (CH_3COOH)$

$M_{KOH}=0.113 M\\V_{KOH}=79.06 mL$

$V_{CH_3COOH}=95.27 \\\\M_{CH_3COOH)=?????$

$M_{CH3COOH} = \frac{M_{KOH}*V_{KOH}}{V_{CH_3COOH}}$

$M_{CH3COOH} = \frac{0.113*79.06}{95.27}$

$M_{CH3COOH} = 0.094 M$

Moles of $CH_3COOH$ = $95.27* 10^{-3}* 0.094$

=0.0090 moles

Moles of $KOH = 79.06*10^{-3}*0.113$

= 0.0090 moles

The equation for the reaction can be expressed as :

$CH_3COOH$ $+$ $KOH$ -----> $CH_3COO^{-}K^+$ $+$ $H_2O$

Concentration of $CH_3COO^{-$ ion = $\frac{0.0090}{Total volume (L)}$

= $\frac{0.0090}{(95.27+79.06)} *1000$

= 0.052 M

Hydrolysis of $CH_3COO^{-$ ion:

$CH_3COO^{-$ $+$ $H_2O$ -----> $CH_3COOH$ $+$ $OH^-$

$K = \frac{K_w}{K_a} = \frac{x*x}{0.052-x}$

⇒ $\frac{10^{-14}}{1.82*10^{-5}}= \frac{x*x}{0.052-x}$

= $0.5494*10^{-9}= \frac{x*x}{0.052-x}$

As K is so less, then x appears to be a very infinitesimal small number

0.052-x ≅ x

$0.5494*10^{-9}= \frac{x^2}{0.052}$

$x^2 = 0.5494*10^{-9}*0.052$

$x^2 = 0.286*10^{-10$

$x = \sqrt{0.286*10^{-10$

$x =0.535*10^{-5}M$

$[OH] = x =0.535*10^{-5}$

$pOH = -log[OH^-]$

$pOH = -log[0.535*10^{-5}]$

$pOH = 5.27$

pH = 14 - pOH

pH = 14 - 5.27

pH = 8.73

Hence, the pH of the titration mixture = 8.73

8 0

3 years ago

What is the scientific method _ and _

Anettt [7]

A Method of procedure that has characterized natural science in include systematic observation, measurement, and experiment
it also include the formation, testing, and modification of hypothesis

i hope it helps out

7 0

4 years ago

A sample of radium-226 contains 1.0×108 atoms of radium-226. How many atoms of radium-226 will remain in the sample after three

cricket20 [7]

After 3 half lives it will be (1/2)^3 or 1/8 of original

so
1/8 times 10^8=1.25 x 10⁶ atoms left

4 0

3 years ago

(100 POINTS) Write the chemical formula of the ionic compound magnesium chlorate. The magnesium (Mg) ion has a +2 charge. Chlora

antoniya [11.8K]

Answer:

A

Explanation:

since Mg has a charge of +2 and ClO3 has a charge of 1-, you need 2 ClO3 to cancel out the +2 since 2 ClO3 ions would have a 2- charge

6 0

3 years ago