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3 years ago

To determine the pH of a solution using a pH indicator paper, you need a .

Chemistry

2 answers:

bonufazy [111]3 years ago

6 0

PH is the water and it color blue

kherson [118]3 years ago

6 0

Answer:

color key

creating a color key

Have known pH values

Explanation:

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Zinc dissolves in hydrochloric acid to yield hydrogen gas: Zn(s) + 2HCl(aq) --> ZnCl2(aq) + H2(g) When a 12.7 g chunk of zinc

ollegr [7]

Answer:

$\boxed{\text{0.673 mol/L}}$

Explanation:

We are given the amounts of two reactants, so this is a limiting reactant problem.

1. Data:

We know we will need an equation with masses and molar masses, so let’s gather all the information in one place.

M_r: 65.38

Zn + 2HCl ⟶ ZnCl₂ + H₂

m/g: 12.7

V/mL: 5.00×10²

c/mol·L⁻¹: 1.450

2. Moles of each reactant

(a) Moles of Zn

$n = \text{12.7 g Zn} \times \dfrac{\text{1 mol Zn}}{\text{65.38 g Zn}} = \text{0.1942 mol Zn}$

(b) Moles of HCl

V = 5.0× 10² mL = 0.5000 L

$n = \text{0.5000 L HCl}\times \dfrac{\text{1.450 mol HCl}}{\text{1 L HCl}} = \text{0.7250 mol HCl}$

3. Identify the limiting reactant

Calculate the moles of ZnCl₂ obtained from each reactant

(i) From Zn

The molar ratio is 1 mol ZnCl₂:1 mol Zn

$n = \text{0.1942 mol Zn} \times \dfrac{\text{1 mol ZnCl}_{2}}{\text{1 mol Zn}} = \text{0.1942 mol ZnCl}_{2}$

(ii) From HCl

The molar ratio is 1 mol ZnCl₂:2 mol HCl

$n = \text{0.7250 mol HCl} \times \dfrac{\text{1 mol ZnCl}_{2}}{\text{2 mol HCl}} = \text{0.3625 mol ZnCl}_{2}$

Zinc is the limiting reactant, because it produces fewer moles of ZnCl₂.

4. Moles of HCl reacted

The molar ratio is 2 mol HCl:1 mol Zn

$n = \text{0.1942 mol Zn} \times \dfrac{\text{2 mol HCl}}{\text{1 mol Zn}} = \boxed{\text{0.3885 mol HCl}}$

5. Moles of HCl remaining

n = 0.7250 - 0.3885 = 0.3365 mol HCl

6. Concentration of hydrogen ions

The HCl is completely dissociated.

$c = \dfrac{\text{0.3365 mol}}{\text{0.5000 L}} = \textbf{0.673 mol/L}\\\\\text{The concentration of hydrogen ions is $\boxed{\textbf{0.673 mol/L}}$}$

4 0

3 years ago

Why are all molecules not compounds?

Elena-2011 [213]

Answer:

Explanation:

All compounds are molecules, but not all molecules are compounds. That is because a molecule can be made up of two atoms of the same kind, as when two oxygen atoms bind together to make an oxygen molecule. However, all compounds are made up of two or more different types of atoms.

3 0

3 years ago

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The hydrogen gas formed in a chemical reaction is collected over water at 30.0 ∘c at a total pressure of 734 mmhg . part a what

In-s [12.5K]

At a temperature of 30 deg C, the vapour pressure of water H2O is about 32 mm Hg. Therefore at a total pressure f 734 mm Hg, the partial pressure of the Hydrogen gas collected is:

<span>P Hydrogen = 734 mm Hg – 32 mm Hg = 702 mm Hg</span>

6 0

3 years ago

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Which of the following statements is TRUE about the loose rocks on the surface

Ivan

Answer:B

Explanation:

3 0

3 years ago

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A compound made of two elements, iridium (Ir) and oxygen (O), was produced in a lab by heating iridium while exposed to air. The

natima [27]

1) Compund Ir (x) O(y)

2) Mass of iridium = mass of crucible and iridium - mass of crucible = 39.52 g - 38.26 g = 1.26 g

3) Mass of iridium oxide = mass of crucible and iridium oxide - mass of crucible = 39.73g - 38.26g = 1.47g

4) Mass of oxygen = mass of iridum oxide - mass of iridium = 1.47g - 1.26g = 0.21g

5) Convert grams to moles

moles of iridium = mass of iridium / molar mass of iridium = 1.26 g / 192.17 g/mol = 0.00656 moles

moles of oxygen = mass of oxygen / molar mass of oxygen = 0.21 g / 15.999 g/mol = 0.0131

6) Find the proportion of moles

Divide by the least of the number of moles, i.e. 0.00656

Ir: 0.00656 / 0.00656 = 1

O: 0.0131 / 0.00656 = 2

=> Empirical formula = Ir O2 (where 2 is the superscript for O)

Answer: Ir O2

5 0

3 years ago

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