What precipitate forms when aqueous soulutions of Potassium Chloride, Sodium Sulfide, Iron(II) Nitrate are simultaneously mixed? Show the molecular and net ionic equation for the reaction.

Draw Lewis dot structure (CH3)4 NCL A SALT

Which of the following species represents an exception to the octet rule?

Calculate the pH of a solution prepared by mixing 300mL of 0.25M sodium hydrogen ascorbate and 150mL of 0.2M HCl plus water to a final volume of 1 liter. The Ka of ascorbic acid is 5.0 x 10^-5

Calculate the standard cell potential for each of the following electrochemical cells.

Part A

Ni2+(aq)+Mg(s)→Ni(s)+Mg2+(aq)

Express your answer using two decimal places.

E∘cell = _____  V

Part B

2H+(aq)+Fe(s)→H2(g)+Fe2+(aq)

Express your answer using two decimal places

E∘cell =_______ V

Part C

2NO−3(aq)+8H+(aq)+3Cu(s)→2NO(g)+4H2O(l)+3Cu2+(aq)

Express your answer using two decimal places.

E∘cell = ________V

b. A graduated cylinder contains 45.0mL of water. When a metal rod is submerged into the water, the liquid level rises to 50.0mL. What is the volume of the metal rod in cm³? If the metal rod weighed 55.0g, what is the density of the metal rod in g/mL and g/cm³?

c. What is the mass of a substance that has a density of 8.0g/cm³ and a volume of 125cm³?

d. Determine the volume of a substance that has a mass of 750.0g and a density of 2.5g/mL.

e. A student finds that a piece of metal has a mass of 12.54g. When the metal is placed inside a flask that has a volume of 25.00mL, the student finds that 20.54g of water is required to finish filling the flask with the metal in it. If the density of water is 0.9970g/cm³, what is the density of the metal?

The pKb values for the dibasic base B are pKb1 = 2.10 and pKb2 = 7.37. Calculate the pH at each of the following points in the titration of 50.0 mL of a 0.55 M B(aq) with 0.55 M HCl(aq).

(a) before addition of any HCl

(b) after addition of 25.0 mL of HCl

(c) after addition of 50.0 mL of HCl

(d) after addition of 75.0 mL of HCl

(e) after addition of 100.0 mL of HCl

You have 625 mL of an 0.23 M acetic acid solution. What volume (V) of 2.10 M NaOH solution must you add in order to prepare an acetate buffer of pH = 5.03? (The pKa of acetic acid is 4.76.)

A 0.5206 g solid sample containing a mixture of LaCl3 (molar mass = 245.26 g/mol) and Ce(NO3)3 (molar mass = 326.13 g/mol) was dissolved in water. The solution was titrated with KIO3, producing the precipitates La(IO3)3(s) and Ce(IO3)3(s). For the complete titration of both La3 and Ce3 , 43.38 mL of 0.1236 M KIO3 was required. Calculate the mass fraction of La and Ce in the sample.​

Fill in the blanks

1. the ____ atoms of the ____ groups and the hydrogen atoms attached to the ____ atoms form ____.

(answer choices; nitrogen, carbon, a-helices or b-pleated sheets, carbonyl, globular of firbrous structures, oxygen, amino, random coil, thiol)

2. In the a helix, hydrogen bonds form between the ____ oxygen atom and the ____ hydrogen atom of a peptide bond in _____. In the B-pleasted sheet, hydrogen bonds form between the ____ oxygen atom and the ____ hydrogen atom of a peptide bond in ____.

(answer choices; parallell sections of a long polypeptide chain, the next amino acid unit, carboxyl, the next turn of the helical chain, thiol, amino, carbonyl)

What are some of the key characteristics of unknown sample of an aqueous solution containing an ionic compound?

Specific questions:

1. Given that the cation is from Group 1A, what is the identity of the group 1A metal ion in your solution?

2. Given that the ionic compound contains either chloride or hydroxide, how can you determine which? (Two pieces of evidence are required and one must be related to solubility rules)

3. What is the concentration of your solution? (Your unknown sample is known to be about 1 M, but you need to determine the concentration to 3 significant figures using titration. You should plan ahead so that you know approximately what volume of your sample you will need in order to use approximately 25 mL of 0.100 M sulfuric acid for the titration).

I'm confused as to how I would go about figuring out these things when even actual information.

The enthalpy of combustion, ΔH, for benzoic acid, C₆H₅COOH, is -3226 kJ/mol. When a sample of benzoic acid was burned in a calorimeter (at constant pressure), the temperature of the calorimeter and contents rose from 23.20°C to 28.40°C. The heat capacity of the calorimeter and contents was 12.41 kJ/ °C. What mass of benzoic acid was burned?

1.(a) What is a chain reaction?

(b) Why is monobromination of ethane a more practical reaction than the monobromination of propane?

(c) Write the mechanism involved in the chain reaction of monbromination of propane. State the experimental conditions, major and minor products.

Name each of the steps. Explain your answer.

(d) Draw the bond-line formula of 3,4-dimethylhexane.
Is geometric isomerism observed in 3,4-dimethylhexane?
What structural features must be present for stereoisomers to exist?

thanks

1. Calcium oxalate monohydrate, CaC2O4•H2O, is stable up to ~100˚C, but will release the incorporated water molecule when heated to 300˚C, according to the following reaction:

CaC2O4•H2O(s) → CaC2O4(s) + H2O(g)

If a 4.1754 g sample of calcium oxalate monohydrate is heated to 300˚C, what should be the mass (g) of the resulting calcium oxalate?

2. An unknown sample of ore with a mass of 506.1 g is allowed to react with excess magnesium and ammonia, NH3, in order to analyze for phosphate, PO43-, according to the following precipitation reaction:

2PO43-(aq) + 2Mg2+(aq) + 2NH3(aq) + 2H2O(l) → Mg2(P2O7)(s) + 2NH3(aq) + 2OH-(aq) + H2O(l)

After the precipitated Mg2(P2O7) is carefully rinsed and dried, the mass is determined to be 0.09870 mg.
Assuming all phosphorous originally present in the ore was in the form of phosphate, what was the original mass (μg) of phosphorous in the ore sample?

3. An unknown organic compound was produced by students in the O-chem lab. According to their records, this compound should only contain carbon and hydrogen atoms. A combustion analysis is performed on the sample.

When 0.1727 g of the sample is burned in the presence of excess oxygen, the magnesium perchlorate cartridge increases 0.24889 g and the ascarite cartridge increases 0.53094 g.

What is the percent C (w/w) in the sample?

4. What is the percent H (w/w) in the sample?

5. What is the empirical formula for the unknown compound?

Consider the reaction

Mg(s)+Fe2+(aq)→Mg2+(aq)+Fe(s)

at 63 ∘C , where [Fe2+]= 2.90 M and [Mg2+]= 0.210 M .

Part A

What is the value for the reaction quotient, Q, for the cell?

Express your answer numerically.

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Correct

Part B

What is the value for the temperature, T, in kelvins?

Express your answer to three significant figures and include the appropriate units.

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Correct

Part C

What is the value for n?

Express your answer as an integer and include the appropriate units (i.e. enter mol for moles).

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Correct

Part D

Calculate the standard cell potential for

Mg(s)+Fe2+(aq)→Mg2+(aq)+Fe(s)

Express your answer to three significant figures and include the appropriate units.

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Correct

Part E

What is the cell potential for the reaction

Mg(s)+Fe2+(aq)→Mg2+(aq)+Fe(s)

at 63 ∘C when [Fe2+]= 2.90 M and [Mg2+]= 0.210 M .