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3 years ago

Describe the difference between an independent and dependent valuable?

Chemistry

1 answer:

kolbaska11 [484]3 years ago

7 0

Answer:

A dependent valuable is a valuable whose variation depend on another variable usually the independent variable. An independent variable is a variable whose variation do not depend on another variable but the reseacher experimenting.

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The boiling point of water is 100.00 °C at 1 atmosphere.

Oksana_A [137]

Answer:

The solution's boiling point is 100,2°C and its molality is 0,13 m

Explanation:

This is the colligative propertie about elevation of boiling point

ΔT = Kb . m . i where

ΔT is the difference between T° at boiling point of the solution - T° at boiling point of the solvent pure

Kb means ebulloscopic constant (<u><em>0,52 °C.kg/m .- a known value for water</em></u>)

m means molality (moles of solute in 1kg of solvent)

i means theVan 't Hoff factor ( degree of dissociation for a compound)

IT HAS NO UNITS

NiI2 ---> Ni2+ + 2I- (we have 1 Ni2+ and 2 I-), the i for this, is 3

The 11,11 g of the salt are in 272,2g of water but I need to know how many mass of the salt is in 1000 g of water (1000 g is 1 kg) so the rule of three is:

272,2g ____ 11,11g

1000g _____ (1000 g . 11,11g) / 272,2g = 40,81g

As the molar mas of NiI2 is 312.5 g/mol, the moles of salt are, mass/molar mass, 40,81g /312.5 g/mol = 0,130 moles

T° of b p sl - 100°C = 0,52 °C.kg/m . 0,130 m/kg . 3

T° of boiling point solution = (0,52 °C.kg/m . 0,130 m/kg . 3) + 100°C

T° of boiling point solution = 100,2°C

4 0

3 years ago

In acidic aqueous solution, the purple complex ion Co(NH3)5Br2+ undergoes a slow reaction in which the bromide ion is replaced b

kirill115 [55]

Answer:

A) 0.065 M is its molarity after a reaction time of 19.0 hour.

B) In 52 hours $[Co(NH_3)5Br]^{2+}$ will react 69% of its initial concentration.

Explanation:

$Co(NH_3)_5(H_2O)_3+[Co(NH_3)5Br]^{2+}(Purple)(aq)+H_2O(l)\rightarrow [Co(NH_3)_5(H_2O)]^{3+}(Pinkish-orange)(aq)+Br^-(aq)$

The reaction is first order in $[Co(NH_3)5Br]^{2+}$ :

Initial concentration of $[Co(NH_3)5Br]^{2+}$ = $[A_o]=0.100 M$

a) Final concentration of $[Co(NH_3)5Br]^{2+}$ after 19.0 hours= $[A]$

t = 19.0 hour = 19.0 × 3600 seconds ( 1 hour = 3600 seconds)

Rate constant of the reaction = k = $6.3\times 10^{-6} s^{-1}$

The integrated law of first order kinetic is given as:

$[A]=[A_o]\times e^{-kt}$

$[A]=0.100 M\times e^{-6.3\times 10^{-6} s^{-1}\times 19.0\times 3600 s}$

$[A]=0.065 M$

0.065 M is its molarity after a reaction time of 19.0 h.

Initial concentration of $[Co(NH_3)5Br]^{2+}$ = $[A_o]=x$

Final concentration of $[Co(NH_3)5Br]^{2+}$ after t = $[A]=(100\%-69\%) x=31\%x=0.31x$

Rate constant of the reaction = k = $6.3\times 10^{-6} s^{-1}$

The integrated law of first order kinetic is given as:

$[A]=[A_o]\times e^{-kt}$

$0.31x=x\times e^{-6.3\times 10^{-6} s^{-1}\t}$

t = 185,902.06 s = $\frac{185,902.06 }{3600} hour = 51.64 hours$ ≈ 52 hours

In 52 hours $[Co(NH_3)5Br]^{2+}$ will react 69% of its initial concentration.

6 0

3 years ago

What mass, in grams, of sodium sulfate is needed to make 230.5 g of a 3.5 % (m/m) aqueous solution of sodium sulfate?

andreev551 [17]

The percent concentration of a solution can be calculated from; mass of solute /mass of solution * 100. The mass of the solute here is 8.1 g.

<h3>What is concentration?</h3>

The term concentration refers to the amount of solute presnt in a solution. There are many ways of expressing concentration such as molarity, molality and percentage.

Here;

mass of solution = 230.5 g

Percent of solute = 3.5 %

3.5 = x/ 230.5 * 100

3.5 = 100x/230.5

230.5(3.5) = 100x

x = 230.5(3.5) /100

x = 8.1 g

Learn more about percent concentration: brainly.com/question/202460?

7 0

1 year ago

Which solution below has the highest concentration of hydroxide ions?a. pH= 3.21b. pH= 7.00c. pH= 7.93d. pH= 12.59e. pH= 9.82

Sloan [31]

Answer:

<em>The solution that has the highest concentration of hydroxide ions is </em><u>d. pH = 12.59.</u>

Explanation:

You can solve this question using just some chemical facts:

pH is a measure of acidity or alkalinity: the higher the pH the lower the acidity and the higher the alkalinity.
The higher the concentration of hydroxide ions the lower the acidity or the higher the alkalinity of the solution, this is the higher the pH.

Hence, since you are asked to state the solution with the highest concentration of hydroxide ions, you just pick the highest pH. This is the option d, pH = 12.59.

These mathematical relations are used to find the exact concentrations of hydroxide ions:

pH + pOH = 14 ⇒ pOH = 14 - pH

pOH = - log [OH⁻] ⇒ $[OH^-]=10^{-pOH}$

Then, you can follow these calculations:

Solution pH pOH [OH⁻]

a. 3.21 14 - 3.21 = 10.79 antilogarithm of 10.79 = 1.6 × 10⁻¹¹

b. 7.00 14 - 7.00 = 7.00 antilogarithm of 7.00 = 10⁻⁷

c. 7.93 14 - 7.93 = 6.07 antilogarithm of 6.07 = 8.5 × 10⁻⁷

d. 12.59 14 - 12.59 = 1.41 antilogarithm of 1.41 = 0.039

e. 9.82 14 - 9.82 = 4.18 antilogarithm of 4.18 = 6.6 × 10⁻⁵

From which you see that the highest concentration of hydroxide ions is for pH = 12.59.

5 0

2 years ago

Which of the following represents the atomic number of an element?

Anna11 [10]

Answer:

The atomic number is the number of protons in the nucleus

4 0

2 years ago

Describe the difference between an independent and dependent valuable￼?

Describe the difference between an independent and dependent valuable?