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3 years ago

Which statements are true about Figure I and Figure II below? (Check all that apply)

Chemistry

1 answer:

Scilla [17]3 years ago

5 0

Both figures are mixtures,

Figure II is a heterogenous mixture

Figure I is a homogenous mixture

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How many moles of oxygen are produced when 2 mol of potassium chlorate (KClO3) decompose

ioda

Keep in mind that when two moles of potassium chlorate are decomposed, 3 moles of oxygen are produced.Think of the coefficients: since the mole ratio is 2 to 3, it means that 2 mol KClO3 will turn into 3 mol O2.

2kclO3->2kcl+3O2

4 0

3 years ago

On a cold winter's day, if you left a cup of water sitting outside, it could freeze. Heat is transferred out of the water. Descr

agasfer [191]

Well, when you leave the water outside, the molecules start to lose some thermal energy and they stop moving, making them more solid and less able to move around. Then, the water turns into ice.

3 0

4 years ago

Read 2 more answers

A cylinder is filled with 10.0 L of gas and a piston is put into it. The initial pressure of the gas is measured to be 273. kPa.

Ann [662]

P2 = 54.6 kPa

Explanation:

Given:

V1 = 10.0 L. V2 = 50.0 L

P1 = 273 kPa. P2 = ?

We can use Boyle's law to solve this problem.

P1V1 = P2V2

Solving for P2,

P2 = (V1/V2)P1

= (10.0 L/50.0 L)(273 kPa)

= 54.6 kPa

5 0

3 years ago

A 1.00 g sample of n-hexane (C6H14) undergoes complete combustion with excess O2 in a bomb calorimeter. The temperature of the 1

Nadya [2.5K]

Answer:

-5,921x10⁶J/mol

Explanation:

Internal energy change (ΔU) for the reaction of combustion in the bomb calorimeter is:

ΔU = q calorimeter + q solution

Where:

q calorimeter is Ccal×ΔT (Ccal=4042J/°C) and (ΔT is 29,30°C-22,64°C=6,66°C)

q solution is c×m×ΔT (c= 4.184 J/g°C), (m=1502g H₂O), (ΔT is 29,30°C-22,64°C=6,66°C)

Replacing:

ΔU = 26920J + 41854J = 68774 J

This energy is per g of n-hexane, now, per mole of n-hexane:

$\frac{68774J}{1gHexane} *\frac{86,1g}{1mol}$ = -5,921x10⁶J/mol

-negative because the energy is produced-

I hope it helps!

5 0

4 years ago

Read 2 more answers

Which statements are true? Δ???? for an exothermic reaction is positive. Δ???? for an endothermic reaction is positive. The evap

LuckyWell [14K]

Answer: The true statements are $\Delta H$ for an endothermic reaction is positive, a combustion reaction is exothermic and when energy is transferred as heat from the system to the surroundings, $\Delta H$ is negative.

Explanation:

There are 2 types of chemical reactions categorized into heat change:

Endothermic reactions: These reactions are defined as the reactions in which energy is absorbed by the system from the surroundings. The $\Delta H$ for these reactions is always positive. For Example: Changing of water into water vapor.
Exothermic reactions: These reactions are defined as the reactions in which energy is released by the system to the surroundings. The $\Delta H$ for these reactions is always negative. For Example: Combustion reactions.

Combustion reactions are defined as the reactions in which a hydrocarbon reacts with oxygen gas to produce carbon dioxide and water. Heat is released during these reactions. Thus, it is considered as exothermic reactions.

Hence, the true statements are $\Delta H$ for an endothermic reaction is positive, a combustion reaction is exothermic and when energy is transferred as heat from the system to the surroundings, $\Delta H$ is negative.

6 0

4 years ago