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2 years ago

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A student places 1.38g of unknown metal at 99.6C into 60.50g of water at 22.1C. The entire system reaches a uniform temperature

at 31.6C. Calculate the specific heat of the metal

1 answer:

stiv31 [10]2 years ago

8 0

Explanation:

Heat energy lost by metal = Heat energy gained by water.

(0.00138kg) * c * (99.6-31.6) = (0.006050kg) * 4.148 * (31.6-22.1)

c = 2.541J/kg°C

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A 60.0 mL solution of 0.112 M sulfurous acid (H2SO3) is titrated with 0.112 M NaOH. The pKa values of sulfurous acid are 1.857 (

djverab [1.8K]

Answer:

a)4.51

b) 9.96

Explanation:

Given:

NaOH = 0.112M

H2S03 = 0.112 M

V = 60 ml

H2S03 pKa1= 1.857

pKa2 = 7.172

a) to calculate pH at first equivalence point, we calculate the pH between pKa1 and pKa2 as it is in between.

Therefore, the half points will also be the middle point.

Solving, we have:

pH = (½)* pKa1 + pKa2

pH = (½) * (1.857 + 7.172)

= 4.51

Thus, pH at first equivalence point is 4.51

b) pH at second equivalence point:

We already know there is a presence of SO3-2, and it ionizes to form

SO3-2 + H2O <>HSO3- + OH-

$Kb = \frac{[ HSO3-][0H-]}{SO3-2}$

$Kb = \frac{10^-^1^4}{10^-^7^.^1^7^2} = 1.49*10^-^7$

[HSO3-] = x = [OH-]

mmol of SO3-2 = MV

= 0.112 * 60 = 6.72

We need to find the V of NaOh,

V of NaOh = (2 * mmol)/M

= (2 * 6.72)/0.122

= 120ml

For total V in equivalence point, we have:

60ml + 120ml = 180ml

[S03-2] = 6.72/120

= 0.056 M

Substituting for values gotten in the equation $Kb=\frac{[HSO3-][OH-]}{[SO3-2]}$

We noe have:

$1.485*10^-^7=\frac{x*x}{(0.056-x)}$

$x = [OH-] = 9.11*10^-^5$

$pOH = -log(OH) = -log(9.11*10^-^5)$

=4.04

pH = 14- pOH

= 14 - 4.04

= 9.96

The pH at second equivalence point is 9.96

4 0

2 years ago

The volume of hcl gas required to react with excess ca to produce 11.4 l of hydrogen gas at 1.62 atm and 62.0 °c is ________ l.

seropon [69]

Answer:

22.8 L

Step-by-step explanation:

We can use <em>Gay-Lussac's Law of Combining Volumes</em> to solve this problem:

Gases <em>at the same temperature and pressure</em> react in simple whole-number ratios.

1. Write the chemical equation.

Ratio: 2 L 1 L

Ca(s) + 2HCl(g) ⟶ CaCl₂(s) + H₂(g)

V/L: 11.4

2. Calculate the volume of HCl.

According to the law, 2 L of HCl form 1 L of H₂.

Then, the conversion factor is (2 L HCl/1 L H₂).

Volume of HCl = 11.4 L H₂ × (2 L HCl/1 L H₂)

= 22.8 L HCl

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2 years ago

A column is filled with four different liquids of different densities. A red liquid, a blue liquid, a green liquid, and a purple

zhuklara [117]

4. Blue, Red, Green, Purple

(Lowest densities on the top, highest densities on the bottom)

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2 years ago

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For lunch, a patient consumed 3 oz of skinless chicken, 3 oz of broccoli, 1 medium apple, and 1 cup of nonfat milk (see Table 3.

Volgvan

Lunch of a patient has 3 oz skinless chicken, 3 oz of broccoli, 1 medium apple, and 1 cup of nonfat milk

Energy content of 3 oz skinless chicken is = 110 kcal

Energy content of 3 oz broccoli = 30 kcal

Energy content of 1 medium apple = 60 kcal

Energy content of 1 cup non-fat milk = 90 kcal

So the kilocalories of energy patient obtained from lunch

= 110 kcal+ 30 kcal + 60 kcal + 90 kcal = 290 kcal

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2 years ago

If the patient has to be administered a dosage of 2 tablets every 8 hours for 7 days, what is the number of tablets required for

Lilit [14]

If the patient has to take 2 tablets every 8 hours for 7 days.
24/8=3 3*2=6
this means that he patient will have to take 6 tablets every day.
6*7=42 And the patient must take 42 tablets in all 7 days
Hope this helps! :)

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2 years ago