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3 years ago

What is variable????

Chemistry

2 answers:

emmasim [6.3K]3 years ago

7 0

Answer:

<h3>Variable are all the quantities that could change in an experiment.</h3>

Misha Larkins [42]3 years ago

4 0

Answer:

Basically, a variable is any factor that can be controlled, changed, or measured in an experiment. It's anything that can be changed in the experiment.

Explanation:

Scientific experiments have several types of variables. The independent and dependent variables are the ones usually plotted on a chart or graph, but there are other types of variables you may encounter. The presence/absence of the chemical is the independent variable. The health of the (ex:)rat (whether it lives and can reproduce) is the dependent variable.

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A solution contains [Ba2+] = 5.0 × 10−5 M, [Zn2+] = 2.0 × 10−7 M, and [Ag+] = 3.0 × 10−5 M. Sodium oxalate (Na2C2O4) is slowly a

Jet001 [13]

Answer:

BaC₂O₄, then ZnC₂O₄, then Ag₂C₂O₄

Explanation:

1. Calculate the equilibrium concentrations of oxalate ion

Let [C₂O₄²⁻] = c

(a) Barium oxalate

BaC₂O₄ ⇌ Ba²⁺ + C₂O₄²⁻

E/mol·L⁻¹: 5.0 × 10⁻⁵ c

Ksp = [Ba²⁺][C₂O₄²⁻] = 5.0 × 10⁻⁵c = 1.5 × 10⁻⁸

c = (1.5 × 10⁻⁸)/(5.0 × 10⁻⁵) = 3.0 × 10⁻⁴ mol·L⁻¹

(b) Zinc oxalate

ZnC₂O₄ ⇌ Zn²⁺ + C₂O₄²⁻

E/mol·L⁻¹: 2.0 × 10⁻⁷ c

Ksp = [Zn²⁺][C₂O₄²⁻] = 2.0 × 10⁻⁷c = 1.35 × 10⁻⁹

c = (1.35 × 10⁻⁹)/(2.0 × 10⁻⁷) = 6.8 × 10⁻³ mol·L⁻¹

(c) Silver oxalate

Ag₂C₂O₄ ⇌ 2Ag⁺ + C₂O₄²⁻

E/mol·L⁻¹: 3.0 × 10⁻⁵ c

Ksp = [Ag⁺]²[C₂O₄²⁻] = (3.0× 10⁻⁵)²c = 9.0 × 10⁻¹⁰c = 1.1 × 10⁻¹¹

c = (1.1 × 10⁻¹¹)/(9.0 × 10⁻¹⁰) = 0.012 mol·L⁻¹

2. Decide the order of precipitation

BaC₂O₄ will precipitate when c > 3.0 × 10⁻⁴ mol·L⁻¹

ZnC₂O₄ will precipitate when c > 6.8 × 10⁻³ mol·L⁻¹

Ag₂C₂O₄ will precipitate when c > 0.028 mol·L⁻¹

This happens to be the order of increasing concentration of oxalate ion.

The order of precipitation is

BaC₂O₄, then ZnC₂O₄, then Ag₂C₂O₄

4 0

3 years ago

6th grade help me plzzzzzz

Anna [14]

Answer:

<h2><u><em>It's protons and neutrons </em></u></h2>

Explanation:

<h2><u><em>Hope this helps </em></u></h2>

3 0

2 years ago

Select the correct Answers.

Mandarinka [93]

Answer:

3. The temperatures of the two substances equalize.

Explanation:

As two objects at different temperatures are placed in contact, heat is transferred from the warmer to the cooler object until the temperature of the two objects be the same.

The amount of heat that is transferred from the warmer object is equal to the amount of heat that is transferred into the cooler object.

This is in agreement with the law of conservation of energy.
<em>So, the right choice is: 3. The temperatures of the two substances equalize. </em>

8 0

3 years ago

Read 2 more answers

What is the molarity of 225 grams of Cu(NO2)2 in a total volume of 2.59 L?

Kay [80]

Answer:

The molarity is 0.56 $\frac{moles}{L}$

Explanation:

In a mixture, the chemical present in the greatest amount is called a solvent, while the other components are called solutes. Then, the molarity or molar concentration is the number of moles of solute per liter of solution.

In other words, molarity is the number of moles of solute that are dissolved in a given volume.

The Molarity of a solution is determined by:

$Molarity (M)=\frac{number of moles of solute}{Volume}$

Molarity is expressed in units ( $\frac{moles}{liter}$ ).

Then you must know the number of moles of Cu(NO₂)₂. For that it is necessary to know the molar mass. Being:

Cu: 63.54 g/mol
N: 14 g/mol
O: 16 g/mol

the molar mass of Cu(NO₂)₂ is:

Cu(NO₂)₂= 63.54 g/mol + 2*(14 g/mol + 2* 16 g/mol)= 155.54 g/mol

Now the following rule of three applies: if 155.54 g are in 1 mole of the compound, 225 g in how many moles are they?

$moles=\frac{225 g*1 mole}{155.54 g}$

moles= 1.45

So you know:

number of moles of solute= 1.45 moles
volume=2.59 L

Replacing in the definition of molarity:

$Molarity=\frac{1.45 moles}{2.59 L}$

Molarity= 0.56 $\frac{moles}{L}$

<u><em>The molarity is 0.56</em></u> $\frac{moles}{L}$ <u><em></em></u>

5 0

2 years ago

calculate the volume that will be occupied by 350 ml of oxygen measured at 720 mm hg, when the pressure changed to 630 mm hg

likoan [24]

Answer:

406.45mL

Explanation:

The following data were obtained from the question:

V1 = 350mL

P1 = 720mmHg

P2 = 630mmHg

V2 =?

The new volume can be obtain as follows:

P1V1 = P2V2

720 x 350 = 620 x v2

Divide both side by 620

V2 = (720 x 350) /620

V2 = 406.45mL

The new volume of the gas is 406.45mL

8 0

2 years ago

What is variable????​

What is variable????