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3 years ago

Which of the following statements is a correct explanation of what occurs when a substance is heated

Chemistry

1 answer:

Lynna [10]3 years ago

4 0

Answer:

i dont understand the question

Explanation:

i dont understand the question

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Consider the chemical equations shown here.

jarptica [38.1K]

Answer:

-1,300 kJ

Explanation:

P₄ + 3 O₂ ⇒ P₄O₆ ΔH = -1,640.1 kJ (EQ 1)

P₄O₁₀ ⇒ P₄ + 5 O₂ ΔH = 2,940.1 kJ (EQ 2)

These are the equations you are given. You need to make these equations into the equation below.

P₄O₆ + 2 O₂ ⇒ P₄O₁₀ (end equation)

Look at the product side of the end equation. You need to produce P₄O₁₀. In the EQ 2, P₄O₁₀ is on the reactant side. Flip the equation. Since you flipped the equation, the enthalpy will have the opposite sign.

P₄ + 5 O₂ ⇒ P₄O₁₀ ΔH = -2,940.1 kJ

On the reactant side of the end equation, you need P₄O₆ and 2 O₂. First, rearrange the equation so that P₄O₆ is on the right side. In EQ 1, P₄O₆ is on the product side. Flip the equation. Like the last one, the sign will change.

Now, cancel out all possible values. P₄ will cancel out since there is one on each side of the equation. Since there is 5 O₂ on one side and 3 O₂ on the other, subtract the two and put the remainder on the side of the larger value.

P₄ + 5 O₂ ⇒ P₄O₁₀ ΔH = -2,940.1 kJ

P₄O₆ + 2 O₂ ⇒ P₄O₁₀

This should be the resulting equation. Now, add the two enthalpies together to find the overall enthalpy.

-2,940.1 kJ + 1,640.1 kJ = -1,300 kJ

The overall enthalpy is -1,300 kJ.

6 0

4 years ago

Four molecules have carbon as the central atom and hydrogen atoms around it. Which shape would give rise to a polar molecule?

ivann1987 [24]

Answer:

D) Tetrahedral

Explanation:

Hello,

Tetrahedral is a molecular shape that turns out when four bonds and no lone pairs around the central atom in the molecule. The bonded atoms to the central atom lie at the corners of a tetrahedron with 109.5° angles between them. The molecules with an tetrahedral electron pair geometries have $sp^3$ hybridization at the central atom. For instance, both ammonium ion ( $NH_4^+$ ) and methane ( $CH_4$ ) have a tetrahedral molecular geometry.

Best regards.

8 0

4 years ago

How many electrons does calcium hace?

Alja [10]

The number of electrons is 20. hope this helps

4 0

3 years ago

Calculate the specific heat of glass if 13.4 J of energy are required to heat 8.0 g of water by 2.0°C.

Mars2501 [29]

Answer:- Specific heat of glass is $c=0.84\frac{J}{g.^0C}$ .

Solution:- It asks to calculate the specific heat of glass when 13.4 J of heat is required to heat 8.0 g of water by 2.0 degree C.

The equation used for solving this type of problems is:

$q=mc\Delta T$

where, q is the heat energy, m is the mass, c is specific heat and $\Delta T$ is change in temperature.

From given info:

q = 13.4 J

m = 8.0 g

$\Delta T$ = 2.0 degree C

c = ?

Let's plug in the values in the equation and solve it for c:

$13.4J=8.0g*c*2.0 ^0C$

On rearrangement:

$c=\frac{13.4J}{8.0g*2.0^0C}$

$c=0.84\frac{J}{g.^0C}$

So, the specific heat of glass is $c=0.84\frac{J}{g.^0C}$ .

5 0

3 years ago

How do you know if a physical change is taking place or has happened?

labwork [276]

In a chemical reaction, there is a change in the composition of the substances in question; in a physical change there is a difference in the appearance, smell, or simple display of a sample of matter without a change in composition. Although we call them physical "reactions," no reaction is actually occurring.

3 0

4 years ago