Physical or Chemical Change? Burning leaves

Given the unbalanced equation below, how many moles

Svet_ta [14]

Answer: 6 mol Li

Explanation:

The first step is to balance the equation.

2Li+Cl₂⇒2LiCl

We would need our conversions to find the amount of moles of Li needed to produces 6 mol LiCl.

$6molLiCl*\frac{2molLi}{2molLiCl} =6molLi$

8 0

3 years ago

A 14.2% by mass HCl solution has a density of 1.1684 g/mL. What is the concentration of this solution in molarity?

snow_tiger [21]

Answer:

[HCl] = 4.54 M

Explanation:

14.2 % by mass is 14.2 g in 100 g of solution.

Let's calculate the moles of our solute, HCl

14.2 g / 36.45 g/mol = 0.389 mol

Molarity is mol/L (moles of solute in 1L of solution)

Let's determine the volume of solution with density

Solution density = Solution mass / Solution volume

Solution volume = Solution mass / Solution density

Solution volume = 100 g / 1.1684 g/mL → 85.6 mL

For molarity, we need the volume in L. Let's make the unit change.

85.6 mL . 1 L/1000mL = 0.0856L

Molarity is 0.389 mol / 0.0856L → 4.54 M

3 0

3 years ago

FeSO4 • 7H2O

Mrac [35]

Answer:

1. Percent by mass of H₂O = 45.3%

2. Percent by mass of anhydrous Salt (FeSO₄) = 54.7 %

Explanation:

Data Given

Formula of the Molecule = FeSO₄ • 7H₂O

% by mass water (H₂O) = ?

% by mass FeSO₄ = ?

________________________________________

> First of all find the atomic masses of each component in a molecule

For H₂O atomic masses are given below

H = 1 g/mol

O = 16 g/mol

> Then find the total mass of H₂O in haydrated salt

7H₂O = 7 (2x1 +1x16) g/mol

7H₂O = 7 (2+16) g/mol

7H₂O = 7 (18) g/mol

7H₂O = 126 g/mol

> find total Molar Mass of Molecule:

Molar Mass of FeSO₄ • 7H₂O = [56+ 32 + 16x4] + 7(2+16)

Molar Mass of FeSO₄ • 7H₂O = [56+ 32 + 64] + 126

Molar Mass of FeSO₄ • 7H₂O = 278

Now to find the mass by percent of H₂O

Formula used to find the mass by percent of a component

Percent composition of H₂O = mass of H₂O in Molecule / molar mass of FeSO₄ • 7H₂O x 100%

Put the values

Percent by mass of H₂O = 126 (g/mol) / 278 (g/mol) x 100%

Percent by mass of H₂O = 0.4532 x 100%

Percent by mass of H₂O = 45.3%

_______________________________________________

> First of all find the atomic masses of each component in a molecule

For anhydrus salt (FeSO₄) atomic masses are given below

Fe = 56 g/mol

S= 32 g/mol

O = 16 g/mol

> Then find the total mass of FeSO₄ in haydrated salt

FeSO₄ = (56x1 + 32 + 4x16) g/mol

FeSO₄ = ( 56 + 32 + 64) g/mol

FeSO₄ = 152 g/mol

> find total Molar Mass of Molecule:

Molar Mass of FeSO₄ • 7H₂O = [56+ 32 + 16x4] + 7(2+16)

Molar Mass of FeSO₄ • 7H₂O = [56+ 32 + 64] + 126

Molar Mass of FeSO₄ • 7H₂O = 278

Now to find the mass by percent of FeSO₄

Formula used to find the mass by percent of a component

Percent composition of FeSO₄ = mass of FeSO₄ in Molecule / molar mass of FeSO₄ • 7H₂O x 100%

Put the values

Percent by mass of FeSO₄ = 152 (g/mol) / 278 (g/mol) x 100%

Percent by mass of FeSO₄ = 0.547 x 100%

Percent by mass of FeSO₄ = 54.7 %

4 0

4 years ago

Read 2 more answers

Consider four small molecules, A–D, which have the following binding affinities for a specific enzyme (these numbers are the equ

ehidna [41]

Answer:

Binding affinity measures the strength of the interaction between a molecule to its ligand; it is expressed in terms of the equilibrium dissociation constant; and the higher value of this constant, the more weaker the binding between the molecule and the ligand is. On the other hand, small constans means that the interaction is tight. So "C" binds most tightly to the enzyme and "D" binds least tightly.

8 0

4 years ago

During a chemical reaction substances called reactants During a chemical reaction substance called reactants are combined to for

lutik1710 [3]

Answer:

During a chemical reaction, substance called reactants are combined to form a new substance called products.

this sentence describes reaction and products of a chemical reaction

4 0

3 years ago