Is the ability to cause change

Charlie the Chemist heats a 62.51 g piece of copper from 22.9°C to 345.0°C. Calculate the amount

Ivanshal [37]

Mass=m=62.51g
Initial temperature=T_i=22.9°C
Final temperature=T_f=345.0°C
Specific heat of copper=0.0920cal/g°C
∆T=T_f-T_i=345-22.9=322.1°C

$\\ \tt\hookrightarrow Q=mc\Delta T$

$\\ \tt\hookrightarrow Q=62.1(0.0920)(322.1)$

$\\ \tt\hookrightarrow Q=1840.22172cal$

$\\ \tt\hookrightarrow Q=1840.222cal$

$\\ \tt\hookrightarrow Q=1840.2cal$

6 0

3 years ago

4.62 ) (a) Calculate the molarity of a solution made by dissolving 12.5 grams of Na2CrO4 in enough water to form exactly 750 mL

Gelneren [198K]

Answer:

a. [Na₂CrO₄] = 0.10 M

b. 0.017 moles of KBr

Explanation:

Molarity means a sort of concentration which indicates the moles of solute over 1L of solution.

We determine the moles of solute: 12.5 g / 162g/mol = 0.0771 moles

We convert the volume of solution from mL to L = 750 mL . 1L/1000mL = 0.750L

Molarity (mol/L) → 0.0771 mol / 0.750L = 0.10 M

b. In order to determine the moles of solute, with the molarity of solution and the volume we assume:

Molarity = moles of solute /volume of solution

Then, Molarity . Volume of solution (L) = moles of solute

We convert the volume of solution from mL to L = 150 mL . 1L/1000mL = 0.150L

0.112 mol/L . 0.150L = Moles of solute → 0.017 moles of KBr

5 0

4 years ago

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Type Calculations. Given the balanced equation: 2 Al + 3 H2SO4---> Al2(SO4)3 + 3 H2 Molar mass (g/mol): Al=26.98; H2SO4=98.08

Oxana [17]

Answer:

A. 1.88 mol H₂

B. 182 g Al₂(SO₄)₃

C. 54.8%

Explanation:

2 Al + 3 H₂SO₄ ⇒ Al₂(SO₄)₃ + 3 H₂

A. Convert grams of Al to moles. The molar mass is 26.98 g/mol.

(33.8 g)/(26.98 g/mol) = 1.253 mol Al

Use stoichiometry to convert moles of Al to moles of H₂. Looking at the equation, you can see that for every 2 mol of Al consumed, 3 moles of H₂ is produced. Use this relationship.

(1.253 mol Al) × (3 mol H₂)/(2 mol Al) = 1.879 mol H₂

You will produce 1.88 mol of H₂ gas.

B. Again, use stoichiometry. For every 3 moles of H₂SO₄ consumed, 1 mole of Al₂(SO₄)₃ is produced.

(1.60 mol H₂SO₄) × (1 mol Al₂(SO₄)₃/3 mol H₂SO₄) = 0.533 mol Al₂(SO₄)₃

Convert moles of Al₂(SO₄)₃ to grams. The molar mass is 342.15 g/mol.

(0.533 mol) × (342.15 g/mol) = 182.48 g Al₂(SO₄)₃

You will produce 182 g of Al₂(SO₄)₃.

C. Calculate percent yield by dividing the actual yield by the theoretical yield. Multiply by 100%.

(100.0/182.48) × 100% = 54.8%

The percent yield is 54.8%.

7 0

3 years ago

a container holds 6.4 moles of gas. hydrogen gas makes up 25% of the total moles in the container. if the total pressure is 1.24

Mekhanik [1.2K]

The total pressure of the mixture of gases is equal to the sum of the pressure of each gas as if it is alone in the container. The partial pressure of a component of the mixture is said to be equal to the product of the total pressure and the mole fraction of the component in the mixture.<span>

Partial pressure of hydrogen gas = 1.24 atm x .25 = 0.31 atm
<span>Partial pressure of the remaining = 1.24 atm x (1-.25) = 0.93 atm </span></span>

5 0

3 years ago

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Composition of matter (compound, mixture, element)

slava [35]

Explanation:

Matter can be classified into two broad categories: pure substances and mixtures. ... A material composed of two or more substances is a mixture. Elements and compounds are both examples of pure substances. A substance that cannot be broken down into chemically simpler components is an elementOne useful way of organizing our understanding of matter is to think of a hierarchy that extends down from the most general and complex to the simplest and most fundamental (Figure 3.4.1 ). Matter can be classified into two broad categories: pure substances and mixtures. A pure substance is a form of matter that has a constant composition (meaning that it is the same everywhere) and properties that are constant throughout the sample (meaning that there is only one set of properties such as melting point, color, boiling point, etc. throughout the matter). A material composed of two or more substances is a mixture. Elements and compounds are both examples of pure substances. A substance that cannot be broken down into chemically simpler components is an element. Aluminum, which is used in soda cans, is an element. A substance that can be broken down into chemically simpler components (because it has more than one element) is a compound. For example, water is a compound composed of the elements hydrogen and oxygen. Today, there are about 118 elements in the known universe. In contrast, scientists have identified tens of millions of different compounds to date.

7 0

3 years ago

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