what is the number of valence electrons in sodium?

Answer: 1 mol Al2O3/102.0 g Al2O3

Your best answer would be D

Answer: the sum of the neutrons and protons

Explanation:

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.  Protons and neutrons are located in the nucleus and contributes to the mass of an atom.

Mass number = Number of protons + Number of neutrons

Atomic number is defined as the number of protons or number of electrons that are present in an atom.

Atomic number = Number of electrons = Number of protons

Hence, sum of neutrons and protons define the mass number.

 decomposition and melting

Answer:

Decomposition and melting

Explanation:

Decomposition is the process of splitting two or more compounds apart from each other. Usually, the decomposed substance have different chemicals identities hence the reason why it is a chemical process since it causes chemical change. Example is the decomposition of hydrated salts of metals. CuSO4.5H20 is a penta-hydrate salt I.e contains 5 molecules of water. If this compound is heated, two different compounds are formed and changes the chemical identity of the compound. Melting is a process of liquidizing compounds or elements to the point it changes physical state from solid-liquid. Melting does not change the chemical identity of the compound but rather the physical state of the compound.

Answer:

58g for short on the question xD i dont wanna read all he has too looooooooooooooooooooooooooooooooooooooooooooooooooooong

Explanation:

An example of physical weathering has been frost wedging. Thus, option A is correct.

Physical weathering has been defined as the act of breaking of rocks under the influence of physical pressure. The physical weathering can be caused by slowly moving of water, plant roots or ice wedging.

In ice wedging or frost wedging, the water moves in the cracks of rocks and results in the expansion with conversion to solid state. The expansion results in the physical weathering of rocks.

Thus, an example of physical weathering has been frost wedging. Thus, option A is correct.

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The equation for the photosynthesis reaction in which carbon dioxide and water react to form glucose is . The hear reaction is the difference between the bond dissociation energies in the products and the bond dissociation energies of the reactants

The reactant molecules have 12 C = O, 12 H - O bonds while the product molecules have 5 C - C, 7 C – O, 5 H – O, and 6 O = O bonds. The average bond dissociation energies for the bonds involved in the reaction are 191 for C = O, 112 for H – O, 83 C –C, 99 C – H, 86 C – O, 119 O = O.

Substitute the average bond dissociation energies in the equation for and calculate as follows

= [12 (C=O) + 12 (H-O)] – [5(C-C) + 7(C-H) + 7 (C-O) + 5(H-O) + 6(O=O)]

= [12x191 kcal/mol + 12x112 kcal//mol] – [5x83 kcal/mol + 7x99 kcal/mol + 7x86 kcal/mol + 5x112 kcal/mol + 6x119 kcal/mol]

= 3636 kcal/mol – 2984 kcal/mol = 652 kcal/mol x 4.184 Kj/1kcal = 2.73x10^3 kJ/mol

So, enthalpy change for the reaction is 652 kcal/mol or 2.73x10^3 kJ/mol

To estimate ΔH for the reaction, calculate the sum of bond dissociation energies for all the bonds broken and formed. Use the bond dissociation energies from Table 7.1 and convert ΔH from kJ to kcal.

To estimate ΔH for the reaction, we need to calculate the sum of the bond dissociation energies for all the bonds broken and formed. C6H12O6 has five C−C bonds, seven C−H bonds, seven C−O bonds, and five O−H bonds. Using the bond dissociation energies from Table 7.1, we can calculate the total energy of the bonds broken and formed and determine the enthalpy change. Each bond's energy is multiplied by the number of moles of that bond in the reaction.

The bond dissociation energy values are given in kJ/mol, so we need to convert to kcal. 1 kcal is equal to 4.184 kJ. Therefore, we can divide the calculated enthalpy change value by 4.184 to get the value in kcal.

Here is the step-by-step calculation:

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Answer:

B

Explanation:

Why? Because if you search or look at a inside of a battery you'll see that it is made up of weird chemicals and stuff

(If you actually do look inside of a battery make sure to dispose correctly because it is dangerous.)

The type of energy present in the batteries of a flashlight is chemical energy.

Chemical energy is the energy stored in the bonds between atoms and molecules. When the batteries are used, the chemical energy is converted into electrical energy, which powers the flashlight.

Mechanical energy is the energy of motion. Radiant energy is the energy of light. Both of these types of energy are not present in batteries.

The chemical energy in the batteries is stored in the form of ions. When the batteries are used, the ions react with each other and release electrons. The electrons flow through the flashlight, creating an electric current. The electric current powers the light bulb in the flashlight, which produces light.

The chemical energy in the batteries is not infinite. Eventually, the batteries will run out of energy and the flashlight will stop working.

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The smallest part of a compound is called a molecule. The correct answer is option d.

A compound is a substance that is made up of two or more different elements, which are chemically bonded to each other in a fixed ratio.

A molecule is the smallest part of a compound that retains the chemical properties of that compound. It is made up of two or more atoms that are chemically bonded together. When atoms combine to form molecules, they share electrons to achieve a stable electron configuration.

Therefore, a molecule is the smallest part of a compound. Option d is the correct answer.

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Due to mass conservation, the weight of the resulting products is the same as the reactants that participated in the reaction, 2 grams of reactant have been consumed.

If you break an element into its smallest particles, you will get atoms, because all matter, with elements, is made up of atoms.

Chemical elements are pure forms of matter that are present on the earth. They are made up of single types of atoms. And they are also found mixing with other substances on the earth. There are 118 elements in the periodic table.

Atoms are the smallest and basic particle form of which all matter is made up. They are made up of charged particles which are electrons, neutrons, and protons. In the center of the atom, there is a nucleus. Atoms are divisible particles.

As, all matters are made up of atoms, elements are also made up of atoms, so breaking of elements would give atoms.

Thus, you will get atoms by breaking the elements.

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“Models are developed when a scientist’s creativity and insight are combined with data and observations about many similar scenarios”. Models are used for a lot of things in science. As we know everything has advantages and disadvantages, and the same applies to models. Models help us illustrate the concept and formulate hypothesis. When models are used, the scientists are able to notice patterns and develop and revise representation that become a useful model, which makes their scientific knowledge stronger and helps them understand more about the nature of science. Models are a simplified representation. One of the biggest advantages of the model is, that it allows you to have a look at things which are too small such as atoms or too big such as the solar system.

Although, having many benefits, models have quite a number of disadvantages. Models sometimes oversimplify the process therefore leading to a misunderstanding. As models are supposed to be a simplified representation, they will not be complex, which means they will lack detail. For Example “our particle model explains many things about matter, it is not comprehensive — for example, it cannot predict why certain materials have different electrical properties. We could add further refinements that are outside the scope of this course to enable it to do so, but it would make our model so complicated that it would no longer be useful to us”

Final answer:

In nuclear fusion, two or more atomic nuclei combine to form a new element or different atom (A), such as helium from hydrogen. Some of the mass is converted into energy, not resulting in pure energy only. Fusion powers stars and releases significant energy in the process.

Explanation:

The result of nuclear fusion reactions is (A) a new element or different atom formed from the original two. During a fusion reaction, two or more atomic nuclei collide at very high speed and join to create a new nucleus. An example of this process is the fusion of deuterium and tritium, light isotopes of hydrogen, which combine to form helium and release energy.

This energy release occurs because some of the mass of the fusing nuclei is converted into energy, following Einstein's mass-energy equivalence principle (E=mc²). Therefore, the result is not pure energy but a combination of a new element and released energy. Nuclear fusion is also the process that powers the stars, where hydrogen atoms fuse to form helium, releasing vast amounts of energy in the form of light and heat.

In summary, option (A) a new element or different atom formed from the original two is the correct result of a fusion reaction, as exemplified by the fusion reaction in stars.