can anybody pls help me with chemistry how to balance an equation of class 7 ??? pls
really I don't like chemistry..
I need only the step(s)..

​

Answer:

option a

hope helps you

have a great day

Answer:

[tex] a = \frac {2A - bh}{h} [/tex]

Explanation:

Given the following mathematical expression;

A = ½(a + b)h

To make a the subject of formula (express a in terms of A, b and h);

First of all, we would cross-multiply;

2A = (a + b)h

Opening the bracket, we have;

2A = ah + bh

Rearranging the mathematical expression, we have;

ah = 2A - bh

[tex] a = \frac {2A - bh}{h} [/tex]

Answer:

89.35 hour

Explanation:

Recall :

Charge on 1 electron = 1.6 × 10^-19 C

1 mole contains = 6.023 × 10^23

Therefore, the charge on 1 mole of electron will be :

Charge per electron × 1 mole :

(1.6 × 10^-19) * (6.023 * 10^23) = 96500 C = 1 Farad

1 Farad = 96500 C

Using the formula :

Q = Current(I) * time(t)

Q = I*t

t = Q/I

Current, I = 0.3 A

t = 96500 / 0.3

t = 321666.66 second

t = 321666.66 / 3600 = 89.35 hour

Answer:

1.5L of NaNO3 must be present

Explanation:

That contains 200g of sodium nitrate. Round to 2 significant digits

To solve this question we need to convert the mass of NaNO3 to moles using its molar mass (85g/mol). With the moles and the molar concentration we can find the volume in liters of the solution:

Moles NaNO3:

200g * (1mol / 85g) = 2.353 moles NaNO3

Volume:

2.353 moles NaNO3 * (1L / 1.60moles) =

Answer:

sodium ions and chloride ions

chloride ion

sodium ion

Explanation:

Ionic substances are composed of ions. When you dissolve an Ionic substance in water, the ions that compose the substance together with water molecules are present in solution.

Hence, when sodium chloride is dissolved in water, sodium ions and chloride ions are released in solution.

Water has a dipole moment. Hence, the chloride ions are attracted to hydrogen (the positive end of the dipole) while sodium ions are attracted to oxygen (the negative end of the dipole).

This is how the solid is dissolved in water.

When sodium chloride, NaCl , dissolves in water, the solution contains sodium and chloride ions in addition to the water solvent. The partial charges in water help dissolve the compound as the hydrogen end of water is attracted to the chloride ions and the oxygen end is attracted to the sodium ions.

Those molecules in which positive ion as well as negative ion is present, will show solubility in water.

Sodium chloride (NaCl) is an ionic compound, which dissociates into sodium ion and chloride ion in the water. As in the water H⁺ ions are present which get attracted towards the chloride ions (Cl⁻) and hydroxide ion (OH⁻ ion) get attracted towards the sodium ions (Na⁺) and show complete dissolution.

Hence correct answers are sodium and chloride ions, chloride ion and sodium ion.

To know more about solubility in water, visit the below link:
https://brainly.com/question/16903071

Answer: The osmotic pressure of 5.0g of sucrose solution in 1 L is 271.32 torr.

Explanation:

Given: Mass = 5.0 g

Volume = 1 L

Molar mass of sucrose = 342.3 g/mol

Moles are the mass of a substance divided by its molar mass. So, moles of sucrose are calculated as follows.

[tex]Moles = \frac{mass}{molarmass}\\= \frac{5.0 g}{342.3 g/mol}\\= 0.0146 mol[/tex]

Hence, concentration of sucrose is calculated as follows.

[tex]Concentration = \frac{moles}{Volume (in L)}\\= \frac{0.0146 mol}{1 L}\\= 0.0146 M[/tex]

Formula used to calculate osmotic pressure is as follows.

[tex]\pi = CRT[/tex]

where,

[tex]\pi[/tex] = osmotic pressure

C = concentration

R = gas constant = 0.0821 L atm/mol K

T = temperature

Substitute the values into above formula as follows.

[tex]\pi = CRT\\= 0.0146 \times 0.0821 L atm/mol K \times 298 K\\= 0.357 atm (1 atm = 760 torr)\\= 271.32 torr[/tex]

Thus, we can conclude that the osmotic pressure of 5.0g of sucrose solution in 1 L is 271.32 torr.

Answer:

2

Explanation:

The number of carbon atoms that are sp²-hybridized in this alkene is 2

Because all the single bonded carbon atoms in the alkene are  sp²-hybridized

There are three(3) single formed via sp² orbitals and one ( 1 ) PI bond formed via Pure-P-orbital

attached below is the some part of the solution

Answer:

True

Explanation:

A hypothesis can be proven true through experimentation. For example, if you hypothesize that a balloon with helium will float in the air, and then you test this and the balloon floats, you have just proven that your original hypothesis is true.

Answer:

2 lone pairs, bent

Explanation:

According to the Valence Shell Electron Pair Repulsion Theory, the number of electron pairs on the valence shell of the central atom in a molecule influences the shape of the molecule.

The presence of lone pairs on the valence shell of the central atom causes the observed molecular geometry to deviate from the ideal geometry predicted on the basis of the valence shell electron pair repulsion theory.

SCl2 has four regions of electron density. This means that its electron domain geometry is tetrahedral. However, there are two lone pairs on the valence shell of the central atom hence the observed molecular geometry is bent.

Answer:

A. the Law of Multiple Properties

Answer:

A. the law of multiple proportions

Answer:

a.

[tex]Keq=\frac{[HCO_3^-][OH^-]}{[CO_3^{2-}]}[/tex]

b.

[tex]Keq=[O_2]^3[/tex]

c.

[tex]Keq=\frac{[H_3O^+][F^-]}{[HF]}[/tex]

d.

[tex]Keq=\frac{[NH_4^+][OH^-]}{[NH_3]}[/tex]

Explanation:

Hello there!

In this case, for the attached reactions, it turns out possible for us to write the equilibrium expressions by knowing any liquid or solid would be not-included in the equilibrium expression as shown below, with the general form products/reactants:

a.

[tex]Keq=\frac{[HCO_3^-][OH^-]}{[CO_3^{2-}]}[/tex]

b.

[tex]Keq=[O_2]^3[/tex]

c.

[tex]Keq=\frac{[H_3O^+][F^-]}{[HF]}[/tex]

d.

[tex]Keq=\frac{[NH_4^+][OH^-]}{[NH_3]}[/tex]

Regards!

Explanation:

here is your answer. Hope it helps

Answer: The moles of gas present in the cylinder is 0.34 moles.

Explanation:

Given: [tex]P_{1}[/tex] = 2.7 atm,   [tex]V_{1}[/tex] = 3.1 L,     [tex]T_{1}[/tex] = 300 K

[tex]P_{2}[/tex] = ?,      [tex]V_{2}[/tex] = 9.4 L,       [tex]T_{2}[/tex] = 610 K

Formula used to calculate the final temperature is as follows.

[tex]\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}[/tex]

Substitute the values into above formula as follows.

[tex]\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}\\\frac{2.7 atm \times 3.1 L}{300 K} = \frac{P_{2} \times 9.4 L}{610 K}\\P_{2} = \frac{5105.7}{2820} atm\\= 1.81 atm[/tex]

Now, moles present upon heating the cylinder are as follows.

[tex]P_{2}V_{2} = n_{2}RT_{2}\\1.81 atm \times 9.4 L = n_{2} \times 0.0821 L atm/mol K \times 610 K\\n_{2} = \frac{17.014}{50.081} mol\\= 0.34 mol[/tex]

Thus, we can conclude that moles of gas present in the cylinder is 0.34 moles.

Answer:

Two

Explanation:

Lone pairs are electron pairs on an atom that resides only with one of the atoms in a molecule.

Dinitrogen pentaoxide is shown in the image attached. There are five oxygen atoms and two nitrogen atoms in the molecule. The molecule has a total of 40 valence electrons.

There are two electrons present on the central oxygen atom in the Lewis structure of dinitrogen pentaoxide as shown in the image attached.

Answer:

answer is first one 1 will be less then that of hg coloumn

Answer: 178mph

Explanation:

From the question given, we are informed that the speed limit on parts of the German autobahn was once set at 286 kilometers per hour (km/h). Based on the information, the speed limit in miles per hour will then be:

= 286km/h × 1000m/1km × 1mi/1609m

= 178miles per hour

Therefore, the speed limit is 178mph.

Answer:

About redox reaction which of the given statements are true?

Explanation:

Redox reaction is the one in which both oxidation and reduction reactions take place simultaneously.

For example:

[tex]C(s)+O_2(g)->CO_2(g)[/tex]

In this reaction, carbon undergoes oxidation and oxygen undergoes reduction simultaneously.

During this reaction, mutual exchange of electrosn take place between the oxidant and the reductant.

Among the given options,

Option B. electrons are transferred

and

option C.They include both oxidation and reduction takes place are the correct answers.

Answer:

Hope it is helpful to you

Answer:

The sample should be diluted

Explanation:

According to Beer Lambert's law, the absorbance of a sample depends on the concentration of the sample.

Hence, if the concentration of the sample is very high, the spectrophotometer will also report a very high value of absorbance.

When this is the case, the sample should simply be diluted and the readings are taken again using the spectrophotometer.

Answer:

verdadero/a

falso/b

verdadero/c

Explanation:

Answer:

The correct answer is - no not adhere to the law of mass conservation.

Explanation:

According to the law of mass conservation in an isolated system, the mass can not be created or destroyed and in a chemical or physical change, the mass of products should be always equal to the mass of reactants.

On the basis of the law the mass of the chemical reaction-

Mass of products = mass of reactants

33 g of methane + 289g of oxygen = 189g of carbon dioxide + 30g of water

322g ≠ 219 g

which means this reaction does not adhere to the law of conservation.

Answer:be careful and relax

Explanation:

Answer:

Hahaha be careful and relax

[tex] {\bold{\red{\huge{\mathbb{QUESTION}}}}} [/tex]

Draw the structural model for methanal (using C and H and O).

[tex] \huge\mathbb{\red A \pink{N}\purple{S} \blue{W} \orange{ER}}[/tex]

First place the C and then make a double bonded O atom with it then fill H to complete all valence spaces

Answer:

Explanation:

From the given information:

Camphor may be reduced as readily in the presence of sodium borohydride(NaHB4). The resulting compound which is stereoselective requires 1 mole of sodium borohydride (NaHB4) to reduce 1 mole of camphor in this reaction. The reaction is shown below.

Through the reduction process of camphor, the reducing agent can reach the carbonyl face with a one-carbon linkage. The product stereoisomer is known as borneol.

If the molecular weight of camphor = 152.24 g/mol

and it mass = 200 mg

The its no of moles = 200 mg/ 152.24 g/mol

= 1.3137 mmol

Now the amount of the required mmol for NaBH4 to be consumed in the reaction = 5.2 × 1.3137 mmol

= 6.831 mmol

since the molar mass of NaBH4 = 37.83 g/mol

Then, using the same formula:

No of moles = mass/molar mass

mass = No of moles × molar mass

mass = 6.831 mmol × 37.83 g/mol

mass of NaBH4 used = 258.42 mg  

Answer:

a) Attached below

b)  The presence of racemic mixture found as product in both  cases shows that   products are identical ( i.e. they have same configuration

Explanation:

Diagrams of the products obtained from hydroboration-oxidation of cis-2-butene , hydroboration-oxidation of trans-2-butene.

attached below

The presence of racemic mixture found as product in both  cases shows that   products are identical ( i.e. they have same configuration )

Based on the calculations, the Gibbs's free energy for this chemical reaction is equal to -1,680.906 kJ/mol.

Given the following data:

Gibbs's free energy simply refers to the quantity of energy that is associated with a particular chemical reaction.

Mathematically, the Gibbs's free energy for this chemical reaction can be calculated by using this formula:

ΔG° = ΔH° - ΔS°

Substituting the given parameters into the formula, we have;

ΔG° = -1652 × 10³ - (298 × 0.097)

ΔG° = -1652 × 10³ - 28.906

ΔG° = -1,680.906 kJ/mol.

Read more on Gibbs's free energy here: brainly.com/question/18752494

#SPJ1

Answer:

Tin + silver trioxonitrate V -------->Tin IV nitrate + silver

Explanation:

The term word equation refers to an equation in which the reactants and products are written in words rather than chemical symbols.

Note than tin is above silver in the electrochemical series hence silver will be displaced by tin as follows;

Tin + silver trioxonitrate V -------->Tin IV nitrate + silver

Answer:

a. Na+ is pH neutral

b. Ni2+ = weak acid

c. NH4+ = Weak acid

Explanation:

To know the nature of the cation we need to find the nature of its conjugate base.

If the conjugate base of the ion is a strong base, the ion is neutral.

If the conjugate base is a weak base, the ion is a weak acid:

a. Conjugate base Na+ = NaOH

Sodium hydroxide is a strong base:

Na+ is pH neutral

b. Conjugate base Ni²⁺: Ni(OH)2 is a weak base because is not completely soluble in water. That means:

Ni2+ = weak acid

c. Conjugate base NH4+: NH4OH. Weak base:

NH4+ = Weak acid

Answer:

C

Explanation:

an impure substance made through chemical process