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3 years ago

“Na2SO3” represents sodium sulfite.What does the 4 mean in the formula 4Na2SO3?

Chemistry

2 answers:

Strike441 [17]3 years ago

6 0

The mass of substance which consists the equal number of particles as 12 grams of Carbon-12 is said to be mole.

For example:

The balanced chemical equation for production of water from hydrogen and oxygen is:

$2H_2(g) + O_2(g) \rightarrow 2H_2O(l)$

That means 2 moles of $H_2$ reacts with 1 mole of $O_2$ to give 2 moles of $H_2O$ .

The given formula is $4Na_2SO_3$ .

Hence, 4 represents the number of moles in $4Na_2SO_3$ formula that is 4 moles of $Na_2SO_3$ .

The number of atoms of sodium, $Na$ in $4Na_2SO_3$ is:

$4 \times 2 = 8$

The number of atoms of sulfur, $S$ in $4Na_2SO_3$ is:

$4 \times 1 = 4$

The number of atoms of oxygen in, $O$ in $4Na_2SO_3$ is:

$4 \times 3 = 12$

Masteriza [31]3 years ago

3 0

You would find four put in front of the compound in an equation. This is to indicate that there are four times more moles in the reaction than there is in the specie that has no number in front of it in the reaction.

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Consider the intermediate chemical reactions. 2 equations. First: upper C a (s) plus upper C upper O subscript 2 (g) plus one ha

DochEvi [55]

Answer: When the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation is halved and has its sign changed.

Explanation:

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The overall chemical reaction follows:

$CaO(s)+CO_2\rightarrow CaCO_3(s)$ $\Delta H^o_{rxn}=?$

The intermediate balanced chemical reaction are:

(1) $Ca(s)+CO_2(g)+\frac{1}{2}O_2(g)\rightarrow CaCO_3(s)$ $\Delta H_1=-812.8kJ$

(2) $2Ca(s)+O_2(g)\rightarrow 2CaO(s)$ $\Delta H_2=-1269kJ$

The expression for enthalpy of the reaction follows:

$\Delta H^o_{rxn}=[1\times (\Delta H_1)]+[\frac{1}{2}\times (-\Delta H_2)]$

Hence, when the enthalpy of this overall chemical equation is calculated, the enthalpy of the second intermediate equation is halved and has its sign changed.

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2 years ago

Aqueous acetic acid is neutralized by aqueous potassium hydroxide. True or False

liberstina [14]

Answer:

i think its true but I’m not sure

Explanation:

I know that they can. Be mixed

4 0

3 years ago

Read 2 more answers

The reaction described by H2(g)+I2(g)⟶2HI(g) has an experimentally determined rate law of rate=k[H2][I2] Some proposed mechanism

MatroZZZ [7]

Answer:

Mechanism A and B are consistent with observed rate law

Mechanism A is consistent with the observation of J. H. Sullivan

Explanation:

In a mechanism of a reaction, the rate is determinated by the slow step of the mechanism.

In the proposed mechanisms:

Mechanism A

(1) H2(g)+I2(g)→2HI(g)(one-step reaction)

Mechanism B

(1) I2(g)⇄2I(g)(fast, equilibrium)

(2) H2(g)+2I(g)→2HI(g) (slow)

Mechanism C

(1) I2(g) ⇄ 2I(g)(fast, equilibrium)

(2) I(g)+H2(g) ⇄ HI(g)+H(g) (slow)

(3) H(g)+I(g)→HI(g) (fast)

The rate laws are:

A: rate = k₁ [H2] [I2]

B: rate = k₂ [H2] [I]²

As:

K-1 [I]² = K1 [I2]:

rate = k' [H2] [I2]

Where K' = K1 * K2

C: rate = k₁ [H2] [I]

As:

K-1 [I]² = K1 [I2]:

rate = k' [H2] [I2]^1/2

Thus, just mechanism A and B are consistent with observed rate law

In the equilibrium of B, you can see the I-I bond is broken in a fast equilibrium (That means the rupture of the bond is not a determinating step in the reaction), but in mechanism A, the fast rupture of I-I bond could increase in a big way the rate of the reaction. Thus, just mechanism A is consistent with the observation of J. H. Sullivan

5 0

3 years ago

You are instructed to create 900. mL of a 0.29 M phosphate buffer with a pH of 7.8. You have phosphoric acid and the sodium salt

Aleksandr [31]

Answer:

B and C

Explanation:

When we have to do a buffer solution we always have to choose the reaction that has the pKa closer to the desired pH value. When we find the pKa values we will obtain:

$pKa_1=-Log[6.9x10^-^3]=2.16$

$pKa_2=-Log[6.2x10^-^8]=7.20$

$pKa_3=-Log[4.8x10^-^13]=12.31$

The closer value is pKa2 with a value of 7.2. Therefore we have to use the second reaction. In which $H_2PO_4^-^1$ is the acid and $HPO_4^-^2$ is the base. Therefore the answer for the first question is B and the answer for the second question is C.

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2 years ago

What is science? Why do you think science is important?

ryzh [129]

Answer:

Science is the study of the physical or material world. Science is important because it can answer questions about new ideas and can advance technologies

Explanation:

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3 years ago