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3 years ago

What does it mean when a reaction is spontaneous apex?

1 answer:

7 0

A reaction that is spontaneous means that it can produce products without the supply of energy. The total energy from the reactants reached the activation energy that allow the reaction proceed. An example of this is the decay of a diamond into graphite occuring readily.

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Solutions of sodium carbonate and silver nitrate react to form solid silver carbonate and a solution of sodium nitrate. A soluti

koban [17]

Answer:

1) 2.0 g

2) 0 g

3) 4.17 g

4) 2.57 g

Explanation:

First of all, we need to know the compounds and the reaction. The ion carbonate is $CO3^{-2}$ , and the ion nitrate is $NO3^{-}$ .

Sodium is in group 1, so it must lose one electron to be stable, and be the cation $Na^{+}$ . Silver has only one electron too, so the cation will be $Ag^{+}$ .

To form the chemical compounds, first we put the cation, then the anion, and change their charges without the signal:

Sodium carbonate: Na2CO3

Silver nitrate: AgNO3

Silver carbonate: Ag2CO3

Sodium nitrate: NaNO3

The balanced reaction will be:

Na2CO3 + 2 AgNO3 --> Ag2CO3 + 2 NaNO3

Now, we must check the stoichiometry, which will be 1:2:1:2 (always in number of moles)

The question wants to know the mass value, so we need to know the molar mass of these compounds. Checking the periodic table will see that:

Na = 23 g/mol, C = 12 g/mol, N = 14 g/mol, O = 16 g/mol, Ag = 108 g/mol

So the molar mass of the compounds must be:

Na2CO3 = 106 g/mol (2x23 + 12 + 3x16)

AgNO3 = 170 g/mol (108 + 14 + 3x16)

Ag2CO3 = 276 g/mol (2x108 + 12 + 3x16)

NaNO3 = 85 g/mol

We have a mixture of the reactants, so one probably would be in excess, so, first will need to test. Let's do the stoichiometry calculus using silver nitrate as the limit, so:

1 mol of Na2CO3 ---------- 2 mol of AgNO3

106 g ------------------------------ 2x170 = 340 g

x ------------------------------------ 5.14 g

By a simple direct three rule:

340x = 544.84

x = 1.6 g of Na2CO3

That means that for this reaction, we only need 1.6 g of Na2CO3 to react with 5.14 of AgNO3. How we have 3.60 g of Na2CO3, it is on excess, and all the AgNO3 will be consumed.

1) The mass of Na2CO3 that remains after the reaction will be the initial less the mass that reacted:

m = 3.6 - 1. 6 = 2.0 g

2) All the AgNO3 reacted, so there isn't a mass present after the reaction.

m = 0 g

3) Now, doing the stoichiometry calculus between AgNO3 and Ag2CO3

2 moles of AgNO3 ------------- 1 mol of Ag2CO3

2x170 g ------------------------------- 276 g

5.14 g --------------------------------- x

By a simple direct three rule:

340x = 1418.64

x = 4.17 g of Ag2CO3

4) Now, doing the stoichiometry calculus between AgNO3 and NaNO3

2 moles of AgNO3 ----------------------- 2 moles of NaNO3

2x170 g ---------------------------------------- 2x85 g

5.14 g ------------------------------------------- x

By a simple direct three rule:

340x = 873.8

x = 2.57 g

8 0

3 years ago

How do you balance the equation in number one?

AleksAgata [21]

____NaNO3 + ___PbO --> ___Pb(NO3)2 + ___Na[2]O

To balace the eqaution, you need to have the same number of atoms for each element on both the reactant (left) and product (right) side.

To start off, you wanna know the number of atoms in each element on both sides, so take it apart:

[reactants] [product]
Na- 1 Na- 2

N- 1 N- 2(it's 2 because the the subscript [2] is outside of the parenthesis)

O- 4 O- 7 (same reason as above)

Pb- 1 Pb- 1

Na is not balanced out, so add a coefficient to make it the same on both sides.In this case, multiply by 2:

2NaNO3

Now Na is balanced, but the N and O are also effected by this, so they also have to be multiplied by 2 and they become:

Na- 2 Na- 2

N- 2 N- 2 (it balanced out)

O- 7 (coefficient times subscript, plus lone O) O- 7 (balanced out)

Pb was already balanced so no need to mess with it, just put a 1 where needed (it doesn't change anything).

Now to put it back together, it will look like this:

2NaNO3 + 1PbO --> 1Pb(NO3)2 + 1Na[2]O

3 0

3 years ago

What did Ernest Rutherford discover? How was his model different from Thomson’s?

s2008m [1.1K]

Answer:

thomson developed the chocolate chip method which was the identification of the electrons in the core of an atom. Rutherford discovered that the core was only positive and that the electrons were floating outside of the core.

Explanation:

4 0

3 years ago

How do substances and mixtures diifer

vlabodo [156]

Answer:

hello hope this helps :)

a pure substance consists only of one element or one compound. a mixture consists of two or more different substances, not chemically joined together.

Explanation:

5 0

3 years ago

Tin(ii) fluoride (snf2) is often added to toothpaste as an ingredient to prevent tooth decay. what is the mass of f in grams in

a_sh-v [17]

From the periodic table:
molar mass of Sn = 118.71 grams
molar mass of F = 18.99 grams

This means that:
molar mass of SnF2 = 118.71 + 2(18.99) = 156.69 grams

Therefore, 156.69 grams of SnF2 contains 37.98 grams of F. To know the amount of F in 36.5 grams of the compound, we will simply do a cross multiplication as follows:
mass of F = (36.6 x 37.98) / 156.69 = 8.847 grams

3 0

3 years ago