I’m torn between C and D...HELP

Workout the number of atoms in 0.5 moles of iron?

Luba_88 [7]

Answer:

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8 0

2 years ago

1. The solubility of lead(II) chloride at some high temperature is 3.1 x 10-2 M. Find the Ksp of PbCl2 at this temperature.

solniwko [45]

Answer:

1) The solubility product of the lead(II) chloride is $1.2\times 10^{-4}$ .

2) The solubility of the aluminium hydroxide is $1.6\times 10^{-10} M$ .

3)The given statement is false.

Explanation:

1)

Solubility of lead chloride = $S=3.1\times 10^-2M$

$PbCl_2(aq)\rightleftharpoons Pb^{2+}(aq)+2Cl^-(aq)$

S 2S

The solubility product of the lead(II) chloride = $K_{sp}$

$K_{sp}=[Pb^{2+}][Cl^-]^2$

$K_{sp}=S\times (2S)^2=4S^3=4\times (3.1\times 10^{-2})^3=1.2\times 10^{-4}$

The solubility product of the lead(II) chloride is $1.2\times 10^{-4}$ .

2)

Concentration of aluminium nitrate = 0.000010 M

Concentration of aluminum ion = $1\timed 0.000010 M=0.000010 M$

Solubility of aluminium hydroxide in aluminum nitrate solution = $S$

$Al(OH)_3(aq)\rightleftharpoons Al^{3+}(aq)+3OH^-(aq)$

S 3S

The solubility product of the aluminium nitrate = $K_{sp}=1.0\times 10^{-33}$

$K_{sp}=[Al^{3+}][OH^-]^3$

$1.0\times 10^{-33}=(0.000010+S)\times (3S)^3$

$S=1.6\times 10^{-10} M$

The solubility of the aluminium hydroxide is $1.6\times 10^{-10} M$ .

3.

$Molarity=\frac{Moles}{Volume (L)}$

Mass of NaCl= 3.5 mg = 0.0035 g

1 mg = 0.001 g

Moles of NaCl = $\frac{0.0035 g}{58.5 g/mol}=6.0\times 10^{-5} mol$

Volume of the solution = 0.250 L

$[NaCl]=\frac{6.0\times 10^{-5} mol}{0.250 L}=0.00024 M$

1 mole of NaCl gives 1 mole of sodium ion and 1 mole of chloride ions.

$[Cl^-]=[NaCl]=0.00024 M$

Moles of lead (II) nitrate = n

Volume of the solution = 0.250 L

Molarity lead(II) nitrate = 0.12 M

$n=0.12 M]\times 0.250 L=0.030 mol$

1 mole of lead nitrate gives 1 mole of lead (II) ion and 2 moles of nitrate ions.

$[Pb^{2+}]=[Pb(NO_2)_3]=0.030 M$

$PbCl_2(aq)\rightleftharpoons Pb^{2+}(aq)+2Cl^-(aq)$

Solubility of lead(II) chloride = $K_{sp}=1.2\times 10^{-4}$

Ionic product of the lead chloride in solution :

$Q_i=[Pb^{2+}][Cl^-]^2=0.030 M\times (0.00024 M)^2=1.7\times 10^{-9}$

$Q_i$ ( no precipitation)

The given statement is false.

3 0

4 years ago

The anesthetic procaine hydrochloride is often used to deaden pain during dental surgery. the compound is packaged as a 10.% sol

vichka [17]

10% solution means= $\frac{10g}{100mL}$

= $\frac{0.1g}{1mL}$

= 100 mg/mL

If the dentist inject 0.3 mL, that is equal to 0.3× 100 mg.

If the dentist inject 0.3 mL, that is equal to 30 mg.

So, as anesthetic procaine hydrochloride is often used to deaden pain during dental surgery. the compound is packaged as a 10.% solution (by mass; d = 1.0 g/ml) in water. When our dentist injects 0.30 ml of the solution, 30 mg of procaine hydrochloride (in milligrams) is injected.

6 0

4 years ago

If you want 2 miles of Silver (Ag) from the reaction below, how many grams of copper should you start with? Reaction: Cu + 2AgNO

RSB [31]

Answer:

You should start with 63.54 grams of copper.

Explanation:

The chemical reactions are processes in which the nature of the substances changes, that is, from some initial substances called reactants, totally different ones called products are obtained.

In the chemical reaction, the formulas of reagents and products appear preceded by numbers (the stoichiometric coefficients) that indicate the proportions according to which the transformation occurs. So you can say that stoichiometry establishes relationships between the molecules or elements that make up the reactants of a chemical equation with the products of said reaction. The relationships that are established are MOLAR relationships between the compounds or elements that make up the chemical equation: always in MOLES.

The stoichiometric coefficients of a chemical equation are due to the fact that the atoms present before the reaction must be the same after the reaction, although they will have been rearranged to produce new substances.

If you want 2 moles of silver (Ag), for stoichiometry of the reaction you need a moles of copper Cu. Being the molar mass of copper Cu 63.54 g / mole, then:

1 mole*63.54 g/mole= 63.54 g

You should start with 63.54 grams of copper.

8 0

3 years ago

Citric acid is one component of some soft drinks. Suppose that 8 L of solution are made from 0.24 g of citric acid, C6H8O7. What

stealth61 [152]

Answer:

The correct answer is 0.15 × 10⁻³ M.

Explanation:

C₆H₈O₇ is the molecular formula of citric acid. The mass of the one mole of the substance that comprise Avogadro's no of molecules is termed as the molar mass of the substance.

The molar mass of the citric acid (C₆H₈O₇) will be,

6 × atomic mass of carbon + 8 × atomic mass of hydrogen + 7 × atomic mass of oxygen = 6×12 + 8×1 + 7×16 = 192. Thus, the molar mass of citric acid is 192 g/mol.

The value of the solution given in the question is 8 L.

The mass of citric acid given is 0.24 g or 240 mg, which can also be written as 240/1000 g or 240 × 10⁻³ g.

The number of moles can be calculated by using the formula = mass / molar mass. Thus, by putting the values we get,

= 240 × 10⁻³ g / 192 g/mol

= 1.25 × 10⁻³ mol

The number of moles of the solute present in the 1 liter of the solution is termed as the molarity of the solution. The formula of molarity or M is,

= no of moles of solute / volume of solution in L

Now putting the values we get,

= 1.25 × 10⁻³ mol / 8 L

= 0.156 × 10⁻³ M

Hence, the molarity of citric acid in the given solution is 0.15 × 10⁻³ M

4 0

4 years ago