How many independent variables can you have in an experiment for it to be valid?

A sample of Na2SO4(s) is dissolved in 233 g of water at 298 K such that the solution is 0.298 molar in Na2SO4. A temperature ris

mars1129 [50]

Answer:

The enthalpy of solution of Na2S04 in water is -2.415 * 10³ J/mol

Explanation:

Step 1: Given data

The water has a mass of 233 grams and a density of 0.997 g/mL

⇒volume of water is 233 grams / 0.997 g/ mL = 233.7 mL = 0.2337 L

This makes this a 0.298 molar solution

The temperature rise = 0.129°

The calorimeter constant = 330 J/K

Cp,m(H2O) = 75.3 J/mol*K

Step 2: Calculate the enthalpy of solution

m/M *ΔHsolution,m + mH20/MH20 * CH20,m * ΔT + Ccalorimeter ΔT = 0

This we can rearrange to:

ΔHsolution, m =- ((233/18.02)*75.3 * 0.129 + 330 * 0.129) /(0.2337*0.298)

ΔHsolution, m = -2.415 * 10³ J/mol

The enthalpy of solution of Na2S04 in water is -2.415 * 10³ J/mol

6 0

4 years ago

Write the concentration equilibrium constant expression for this reaction.

Akimi4 [234]

In a chemical reaction, the equilibrium constant refers to the value of its reaction quotient at chemical equilibrium, that is, a condition attained by a dynamic chemical system after adequate time has passed, and at which its composition has no measurable capacity to undergo any kind of further modification.

The given reaction is: HCN (aq) + OH⁻ = CN⁻ (aq) + H2O (l)

The equilibrium constant = product of concentration of products / product of concentration of reactants

(Here, H2O is not considered as its concentration is very high)

So, Keq = [CN⁻] / [HCN] [OH⁻]

8 0

4 years ago

how do I balance this equation? Sodium phosphate reacts with sulfuric acid to form sodium sulfate and phosphoric acid

Dima020 [189]

Answer: The balanced equation is given below:

Explanation:

To balance a chemical equation, we follow law of conservation of mass.

This law states that the total number of individual atoms on reactant side must be equal to the total number of individual atoms on the product side.

The equation for the reaction of sodium phosphate and sulfuric acid follows:

$2Na_3PO_4+3H_2SO_4\rightarrow 3Na_2SO_4+2H_3PO_4$

On reactant side:

Number of sodium atoms: 6

Number of sulfur atoms: 3

Number of hydrogen atoms: 6

Number of oxygen atoms: 20

Number of phosphorous atoms: 2

On product side:

Number of sodium atoms: 6

Number of sulfur atoms: 3

Number of hydrogen atoms: 6

Number of oxygen atoms: 20

Number of phosphorous atoms: 2

As, the number of individual atoms on both the sides of the reaction are equal. Therefore this equation is balanced and follow law of conservation of mass.

3 0

4 years ago

What elements are nonmetals but aren't halogens or noble gasses?

murzikaleks [220]

Answer:

Hydrogen (sometimes considered an alkali metal)

Carbon.

Nitrogen.

Oxygen.

Phosphorus.

Sulfur.

Selenium.

6 0

3 years ago

use the chemical equations for the complete combustion and incomplete combustion of propane to show that matter is conserved in

krok68 [10]

Explanation:

1) Complete combustion of propane gives carbon dioxide gas and water vapors.

The balanced chemical equation is given as:

$C_3H_8(g)+5O_2(g)\rightarrow 3CO_2(g)+4H_2O(g)$

Number of carbon atoms on reactant side = 3

Number of hydrogen atoms on reactant side = 8

Number of oxygen atoms on reactant side = 10

Number of carbon atoms on the product side = 3

Number of hydrogen atoms on the product side = 8

Number of oxygen atoms on the product side = 10

On both the sides numbers, all elements remained the same which indicates that matter remains conserved during the course of a chemical reaction.

2) Incomplete combustion of propane gives carbon dioxide gas, carbon monoxide gas, and water vapors.

The balanced chemical equation is given as:

$2C_3H_8(g)+9O_2(g)\rightarrow 4CO_2(g)+2CO(g)+8H_2O(g)$

Number of carbon atoms on reactant side = 6

Number of hydrogen atoms on reactant side = 16

Number of oxygen atoms on reactant side = 18

Number of carbon atoms on the product side = 6

Number of hydrogen atoms on the product side = 16

Number of oxygen atoms on the product side = 18

On both the sides numbers, all elements remained the same which indicates that matter remains conserved during the course of a chemical reaction.

4 0

3 years ago