7. (a) Using two examples, explain how covalent compounds are formed. [4 marks]
(b) State three physical properties of covalent compounds. [3 marks]
(c) Describe an experiment how you can carry out an experiment to investigate one of the properties mentioned above. [3 marks]

8. (a) Using two examples, explain how covalent compounds are formed. [14 marks]
(b) State three physical properties of covalent compounds.[3 marks]
Describe an experiment how you can carry out an experiment to investigate one of the properties mentioned above. [3 marks]​

Answer:

according to me its c part which is correct

Answer:

Explanation:

Why is there a star * behind the question.

CaCl2

Al2(SO4)3

NaOH

Answer:

0, +2

Explanation:

As a pure element, any element or simple compound has an oxidation number of 0. This makes it a lot easier, and can be applied for almost any element or compound that uses one atom, like F2, O3, Zn, Fe, etc. However, in compounds, Zinc's oxidation number tends to be +2, and this is just a rule that I memorized when I learned this topic. Please let me know if you still need help and I hope you understood!

As a pure element, the oxidation number of zinc is zero, but in compounds such as  [tex]ZnCO_3\\[/tex] its oxidation number is +2.

Oxidation number also called oxidation state, is the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom.

As a pure element, any element or simple compound has an oxidation number of 0. This makes it a lot easier and can be applied for almost any element or compound that uses one atom, like [tex]F_2[/tex], [tex]O_3[/tex], Zn, Fe, etc.

However, in compounds, Zinc's oxidation number tends to be +2.

Learn more about the oxidation number here:

https://brainly.com/question/10079361

#SPJ2

Answer: Sugar solution shows no current flow in an electrolytic cell.

Explanation:

Electric current is the flow of ions or charged species from one point to another.

A solution that does not contain any ions is not able to conduct electric current.

Thus,, we can conclude that sugar solution shows no current flow in an electrolytic cell.

Answer:

kevin is right according to what i see

Answer:

silicon and germanium.

Explanation :

The passage states that at extreme pressures an elemental solid assumes the structure and bonding characteristics of a heavier element in the same column of the periodic table. The structure and bonding of diamond, which is a form of carbon, would therefore be most like other elements in the same group of the periodic table as carbon. This group contains silicon and germanium.

Answer:

3. The mass of ethanol required is approximately 0.522869 g

The mass of ethanoic acid required is approximately 0.68156 g

4. The mass of iron (III) oxide required is approximately 285.952.189.095 tonnes

5. The mass of silver nitrate required is approximately 14.53 grams

6. The mass of copper oxide that would be needed is approximately 31.86 grams

7. a. The mass of the precipitate, Zn(OH)₂ formed is approximately 49.712 grams

b. The mass of the precipitate, Al(OH)₃ formed is approximately 13 grams

c. The mass of the precipitate, Mg(OH)₂, formed is approximately 14.579925 grams

Explanation:

3. The 1 mole of ethanol and 1 mole of ethanoic acid combines to form 1 mole of ethyl ethanoate

The number of moles of ethyl ethanoate in 1 gram of ethyl ethanoate, n = 1 g/(88.11 g/mol) = 1/88.11 moles

∴ The number of moles of ethanol = 1/88.11 moles

The number of moles of ethanoic acid = 1/88.11 moles

The mass of ethanol = (46.07 g/mol) × 1/88.11 moles = 0.522869 g

The mass of ethanoic acid in the reaction = 60.052 g/mol × 1/88.11 moles ≈ 0.68156 g

4. 1 mole of iron(III) oxide reacts with 1 mole of CO₂ to produce 1 mole of iron

The number of moles in 100 tonnes of iron= 100000000/55.845 = 1790670.60614 moles

The mass of iron (III) oxide required = 159.69 × 1790670.60614 = 285952189.095 g ≈ 285.952.189.095 tonnes

5. The number of moles of NaCl in 5 grams of NaCl = 5 g/58.44 g/mol = 0.0855578371 moles

The mass of silver nitrate required, m = 169.87 g/mol × 0.0855578371 moles ≈ 14.53 grams

6. The number of moles of CuSO₄·5H₂O in 100 g of CuSO₄·5H₂O = 100 g/(249.69 g/mol) ≈ 0.4005 moles

The mass of copper oxide required, m = 79.545 g/mol × 0.4005 moles ≈ 31.86 grams

7. a. The number of moles of NaOH in the reaction = 20 g/(39.997 g/mol) ≈ 0.5 moles

2 moles of NaOH produces 1 mole of Zn(OH)₂

0.5 moles of NaOH will produce 0.5 mole of Zn(OH)₂

The mass of 0.5 mole of Zn(OH)₂ = 0.5 mole × 99.424 g/mol = 49.712 grams

The mass of the precipitate, Zn(OH)₂ formed = 49.712 grams

b. 6 moles of NaOH produces 2 moles Al(OH)₃

20 g, or 0.5 mole of NaOH will produce (1/6) mole of Al(OH)₃

The mass of the precipitate, Al(OH)₃ formed, m = 78 g/mol×(1/6) moles = 13 grams

c. 2 moles of NaOH produces 1 mole of Mg(OH)₂, therefore;

20 g or 0.5 moles of NaOH formed (1/4) mole of Mg(OH)₂

The mass of the precipitate, Mg(OH)₂, formed, m = 58.3197 g/mol × (1/4) moles = 14.579925 grams

Answer:

Explanation:

i will show in details how 2 do the 1st Q n u can do the rest by following the way how it is done

3. given C^2H^5OH + CH^3CO^2H → CH^3CO^2C^2H^5 + H^2O

molar ratio of ethanol, ethanoic acid and ethyl ethanoate is 1 : 1 : 1

so mass = no. of moles * molecular mass

for same no. of moles, mass / molecular mass is the same

molecular mass of CH^3CO^2C^2H^5 = 12+1*3+12+16*2+12*2+5*1 = 88

molecular mass of C^2H^5OH = 12*2+1*5+16+1 = 46

molecular mass of CH^3CO^2H = 12+1*3+12+16*2+1 = 60

1 g of ethyl ethanoate = 1/88 mole

it requires 1/88*46 = 0.5227 g of ethanol; and

1/88*60 = 0.6818 g of ethanoic acid

to react together to form 1 g of ethyl ethanoate

Answer:

The answer is A

Explanation:

hope it helps

Answer:

The answer is "[tex]26.47\%[/tex]"

Explanation:

Sodium chloride  solute mass[tex]=36 \ g[/tex]

Solvent water mass[tex]=100\ g[/tex]

Calculating the solution mass = Solute mass  + solvent mass

                                                  [tex]= 36\ g +100\ g\\\\ = 136\ g\\\\[/tex]

Calculating the percentage of concentration:

[tex]= \frac{solute\ mass}{solvent\ mass} \times 100\\\\=\frac{36\ grm}{136\ grm} \times 100\\\\=0.2647 \times 100\\\\=26.47 \%[/tex]

Answer:

4 Fe  +   3 O2    ⇒  2  Fe2O3

Explanation:

iron metal reacts with oxygen gas to produce solid iron (III) oxide.

Fe   +   O2  ⇒  Fe2O3

4 Fe  +   3 O2    ⇒  2  Fe2O3

The balanced chemical equation for the reaction is

4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)

From the question,

We are to write a balanced chemical equation for the reaction of iron metal with oxygen gas to produce solid iron (III) oxide

Iron metal is represented as Fe(s)

Oxygen gas is represented as O₂(g)

and Solid iron (III) oxide is represented as Fe₂O₃(s)

Now, we will write the balanced chemical equation for the reaction

The balanced chemical equation for the reaction is

4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)

This means 4 moles of the iron metal reacts with 3 moles of oxygen gas to produce 2 moles of solid iron (III) oxide.

Hence, The balanced chemical equation for the reaction is

4Fe(s) + 3O₂(g) → 2Fe₂O₃(s)

Learn more here: https://brainly.com/question/23877810

19. place moth balls in the closet and observe after several days.

20. whenever wax or a candle burns it turns from solid to liquid but again at room temperature it turns to solid

21. evaporation, condensation, precipitation

22. it produces new substances

23. vinegar Bubbles when baking soda is added

24. steam

Answer:

letter d

Explanation:

hope it's help you

Answer:

1. Na2CO3 + 2HCl --> 2NaCl + CO2 + H2O

2. 2NaOH + H2SO4 --> Na2SO4 + H2O

3. CaCO3 + 2HCl --> CaCl2 + CO2 + H2O

4. 4Na + O2 --> 2Na2O

Answer:

the answer would be d. usually dull in appearance

Explanation:

because brittle bendable and poor conductor of heat and electricity are all for the non-metals

Answer:

C !!

Explanation:

hope this helps! usually people classify metals based on if they can conduct heat or electricity

The question is incomplete, the complete question is;

As Danny was pouring cereal for his breakfast, he noticed that the cereal box says that the cereal contains 5 milligrams of iron per serving. Danny decided to perform an experiment to test this claim. He found that the cereal contains 4.6 milligrams of iron per serving. Based on Danny's measurement, the value reported on the label is ( CORRECT OR INCCORECT) because A: (IT IS DIFFERENT FROM THE VALUE DANNY MEASURED) B: (IT IS REORTED TO THE NEAREST MILLIGRAM) C: (IT USES THE SAME UNITS THAT DANNY USED).

Answer:

CORRECT because IT IS REORTED TO THE NEAREST MILLIGRAM

Explanation:

In mathematics, values may be rounded up or down as required. In the case of this measurement of cereals by Danny, it is customary to measure the amount of iron per serving to the nearest milligram.

As such, even though Danny found out that the actual amount of iron per serving in the cereal is 4.6 milligrams, the value reported on the cereal box is still correct because it was reported to the nearest milligram hence the value had to be rounded up.

Answer:

The liquid left after crystallization is called Residue

Explanation:

2C +O2 = 2CO

this will be the answer

Answer:

C:Radiation

Explanation:

Pluto

Answer:

i hope this help

Explanation:

Radiation is a method of heat transfer that does not rely upon any contact between the heat source and the heated object as is the case with conduction and convection. Heat can be transmitted through empty space by thermal radiation often called infrared radiation. This is a type electromagnetic radiation.

Answer:

Inference

Explanation:

A conclusion reached on the basis of evidence and reasoning is called an inference.

Answer:

a scientific question

Procedure

Conclusion.

Explanation:

Scientific investigation is usually carried out to explain and give answers to natural phenomenon. Now, this scientific investigation is performed through the three main types as described in the question.

With that being said, the most common parts of all types of investigation are :

1. Scientific question: In this stage, questions are usually asked on the basis of observation made which could be answered.

2. Procedure: In this stage, the dimension of the steps are followed to answer and test the scientific question.

3. Conclusion: This is the primary aim that we check when done with our sample values

Answer:

(i) specific heat

(ii) latent heat of vaporization

(iii) latent heat of fusion

Explanation:

i. Q = mcΔT; identify c.

Here, Q is heat, m is the mass, c is the specific heat and ΔT is the change in temperature.

The amount of heat required to raise the temperature of substance of mass 1 kg by 1 degree C is known as the specific heat.  

ii. Q = mLvapor; identify Lvapor

Here, Q is the heat, m is the mass and L is the latent heat of vaporization.

The amount of heat required to convert the 1 kg liquid into 1 kg vapor at constant temperature.  

iii. Q = mLfusion; identify Lfusion

Here, Q is the heat, m is the mass and L is the latent heat of fusion.  

Here, Q is the heat, m is the mass and L is the latent heat of vaporization.

The amount of heat required to convert the 1 kg solid  into 1 kg liquid at constant temperature.  

(i) c is the molar heat capacity of the substance.

(ii) Lvapor is the latent heat of evaporation of the substance

(iii) Lfusion is the latent heat of fusion of the substance

All the 3 equations fall under Calorimetry.

In all the equation Q is the amount of heat required.

(i) First equation represents the amount of heat required to raise the temperature of a substance of mass m.

                          Q = mcΔT

       here c is the molar heat capacity of the substance and ΔT is the chnage in temperature.

(ii) Second equation represents the amount of heat required to convert a substance of mass m from liquid phase to vapour phase.

                          Q = mLvapor

        here Lvapor is the latent heat of evaporation of the substance

during evaporation no change in temperature occurs.      

(iii) Third equation represents the amount of heat required to convert a substance of mass m from solid phase to liquid phase.

                          Q = mLfusion

        here Lfusion is the latent heat of fusion or melting of the substance

during fusion no change in temperature occurs.    

Learn more about calorimetry:

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Answer:

Calculate the volume (in L) occupied by 3.40 g of NH3 at STP. (STP: 0 degree Celsius and 1 atmosphere of pressure).

Explanation:

To get the volume of ammonia gas at STP, calculate the number of moles of [tex]NH_3[/tex] in the given amount.

Number of moles of [tex]NH_3[/tex] gas is:

[tex]number of moles of NH_3 gas&=\frac{given mass of the gas}{its molecular mass} \\ &=\frac{3.40g}{17.0g/mol} \\&=0.2 mol.[/tex]

Since,

1 mol of any gas at STP occupies ------- 22.4 L of volume.

then,

0.2 mol of [tex]NH_3[/tex] occupies how much volume?

[tex]=>0.2 mol x \frac{22.4 L}{ 1.0 mol} \\=4.48 L[/tex]

Hence, the volume occupied by 3.40 g of ammonia at STP is --- 4.48 L.

I ANSWERED IT BUT SOMEONE SYAYS ITS COPY SO WHAT COULD I DO ;(

Answer:

hope it is helpful to you

Answer:

ethene

Explanation:

The chemical compound acetylene (systematic name: ethyne) has the formula C2H2. It's a hydrocarbon and the most basic alkyne. Because its two carbon atoms are linked together in a triple bond, acetylene is unsaturated as an alkyne.And the ending of acetylene has ene which indicates that it's an alkene .And the ending of acetylene has ene which indicates that it's an alkene.

Answer: i think it is Ethyne

Explanation: because another name for Acetylene is Ethyne which is commonly known

Answer:

B. An alkyne

Explanation:

Octynes are alkynes with one triple bond

Answer:

i hope it will help you

Explanation:

there will be 7 electrons and 9 protons will have 2+ charge.

Answer:

(6 mol)·(-393.5 kJ/mol) + (6 mol)·(-285.83 kJ/mol) - (1 mol)·(-1,273.02 kJ/mol) + (6 mol)·(0 kJ/mol)

Explanation:

Question; From the given options, the chemical reaction in the question is presented as follows;

C₆H₁₂O₆(s) + 6O₂(g) → 6CO₂(g) + 6H₂O(l), given that we have;

[tex]\Delta \text H _f^{\circ}[/tex] for C₆H₁₂O₆ = -1,273.02 kJ/mol

[tex]\Delta \text H _f^{\circ}[/tex] for O₂(g) = 0 kJ/mol

[tex]\Delta \text H _f^{\circ}[/tex] for CO₂(g) = -393.5 kJ/mol

[tex]\Delta \text H _f^{\circ}[/tex] for H₂O(l) = -285.83 kJ/mol

The heat or enthalpy of a reaction,  is given as follows;

[tex]\Delta\text H_{rxn}^{\circ} = \sum \text n \cdot \Delta \text H _f^{\circ}(\text {products}) - \sum \text m \cdot \Delta \text H _f^{\circ}(\text {reactants} \text)[/tex]

Therefore, the equation which should be used to calculate [tex]\Delta\text H_{rxn}^{\circ}[/tex], is given as follows;

[tex]\sum \text n \cdot \Delta \text H _f^{\circ}(\text {products})[/tex] = (6 mol)·(-393.5 kJ/mol) + (6 mol)·(-285.83 kJ/mol)

[tex]\sum \text m \cdot \Delta \text H _f^{\circ}(\text {reactants} \text)[/tex] = (1 mol)·(-1,273.02 kJ/mol) + (6 mol)·(0 kJ/mol)

Therefore;

[tex]\Delta\text H_{rxn}^{\circ}[/tex] = (6 mol)·(-393.5 kJ/mol) + (6 mol)·(-285.83 kJ/mol) - (1 mol)·(-1,273.02 kJ/mol) + (6 mol)·(0 kJ/mol)