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3 years ago

Determine which choice is an example of an endothermic process.

Chemistry

1 answer:

klemol [59]3 years ago

6 0

Answer:

D. Baking bread

Explanation:

In this process, energy is absorbed and in an endothermic process energy is absorbed too.

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10. In which of the following is the symbol for the ion and the total number of electrons it contains given correctly?

dalvyx [7]

Answer:

10. D

9. A

8. A or B

Explanation:

10. Calcium has 20 electrons, but the Calcium ion has 18 electrons.

9. The mass of electrons are negligible.

8. Electrons have a very small mass where some consider it to have no mass.

5 0

3 years ago

Give the symbols for metalloids

Elina [12.6K]

Answer:

The metalloids; boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), polonium (Po) and astatine (At) are the elements found along the step like line between metals and non-metals of the periodic table.

Elements: Germanium; Boron; Arsenic

Explanation:

6 0

2 years ago

How is the number of electrons in an element determined?

elixir [45]

The number of protons, neutrons, and electrons in an atom can be determined from a set of simple rules. The number of protons in the nucleus of the atom is equal to the atomic number (Z). The number of electrons in a neutral atom is equal to the number of protons.

3 0

2 years ago

Read 2 more answers

The question is in the picture below

Rus_ich [418]

Answer:

$\Delta\text{H}_1+2\Delta\text{H}_2-\Delta\text{H}_3$

Explanation:

Hess's Law of Constant Heat Summation states that if a chemical equation can be written as the sum of several other chemical equations, the enthalpy change of the first chemical equation is equal to the sum of the enthalpy changes of the other chemical equations. Thus, the reaction that involves the conversion of reactant A to B, for example, has the same enthalpy change even if you convert A to C, before converting it to B. Regardless of how many steps it takes for the reactant to be converted to the product, the enthalpy change of the overall reaction is constant.

With Hess's Law in mind, let's see how A can be converted to 2C +E.

$\bf{\text{A} \rightarrow 2\text{B}}$ (Δ $\text{H}_1$ ) -----(1)

Since we have 2B, multiply the whole of II. by 2:

$\bf{2\text{B} \rightarrow 2\text{C} +2\text{D}}$ (2Δ $\text{H}_2$ ) -----(2)

This step converts all the B intermediates to 2C +2D. This means that the overall reaction at this stage is $\text{A} \rightarrow 2\text{C} +2\text{D}$ .

Reversing III. gives us a negative enthalpy change as such:

$\bf{2\text{D} \rightarrow \text{E}}$ (-Δ $\text{H}_3$ ) -----(3)

This step converts all the D intermediates formed from step (2) to E. This results in the overall equation of $\text{A} \rightarrow 2\text{C} +\text{E}$ , which is also the equation of interest.