science question hurry please

The reaction produces approximately 4.987 x 10^23 molecules of H2O.

To determine the number of molecules produced, we need to convert the given moles of H2O to molecules. One mole of any substance contains Avogadro's number of molecules, which is approximately 6.02 x 10^23 molecules. Therefore, to convert moles to molecules, we multiply the number of moles by Avogadro's number.

0.829 moles x (6.02 x 10^23 molecules/mole) = 4.987 x 10^23 molecules

This representation shows the two hydrogen atoms (H) bonded to the oxygen atom (O). The angle between the hydrogen-oxygen-hydrogen atoms is approximately 104.5 degrees. Water is a polar molecule, meaning it has a slight electrical dipole moment due to the unequal sharing of electrons between the oxygen and hydrogen atoms, resulting in a partial negative charge on the oxygen atom and partial positive charges on the hydrogen atoms. This polarity gives water unique properties, such as its ability to form hydrogen bonds and its importance in various biological and chemical processes.

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Answer:

The correct statement is :They have identical mass.

Explanation:

Answer:

heyo!

the answer is b

Explanation:

Answer:

Answer:

Option (4)

Explanation:

Index fossils are defined as those fossils that existed for a shorter period of time and are widely distributed on earth. They are abundant. These index fossils because of their short vertical range, are helpful in the determination of the age of the rocks and also to identify the major events that have taken place in the past. For example, the ammonites.

In the given data, the layers comprising of fossils namely A, B, C, D, E and F are provided, where the youngest layer is layer 1 and the oldest layer is layer 6.

From this set of fossils, we can mark that the index fossil within these rock formations is the fossil E. It is because E is the only fossil that is found in the layer 2 which is abundant and is found in a rock layer that belongs to a particular age.

All other fossils i.e. fossils A, B, C, and D  are found in two of the layers, which does not satisfy the condition of an index fossil. They are found in different rock layers belonging to a different time.

Hence, the correct answer is option (4) i.e. fossil E.

The property of the mineral is luster.

A metallic luster would reflect light the same way as a metal would.

D- Luster is your answer

Answer:

I think its c

Explanation:

The correct classification for a mixture with visible solid and liquid that can settle is a heterogeneous mixture and a suspension, like mud in water.

The correct classification of a mixture in which both a solid and a liquid are visible, and in which the particles can settle out, is a heterogeneous mixture and a suspension.

This is because heterogeneous mixtures consist of two or more substances that are not uniformly distributed, and in a suspension, the solid particles are large enough to eventually settle out from the liquid.

An example of such a mixture would be mud mixed with water. This is contrasted with a homogeneous mixture, or a solution, such as salt dissolved in water, where the different substances cannot be visually distinguished even under a microscope.

Crushing a soda can represents a physical change because the change is only in the shape, and the material of the can does not undergo a chemical transformation.

The student's question pertains to distinguishing between physical changes and chemical changes. In the list provided, option A, crushing a soda can, is an example of a physical change. This is because crushing the can changes its shape, but the material it is made of, typically aluminum, is not chemically altered in the process. There is no formation of new substances; the change is merely physical.

Let's review the other options briefly: B. Copper tarnishing is a chemical change because it involves the reaction of copper with sulfur compounds to form a new substance, copper sulfide. C. Baking a cake is a chemical change because new substances are formed as a result of the heat causing chemical reactions between the ingredients. D. Mixing baking soda and vinegar is also a chemical change because it results in the formation of carbon dioxide gas, water, and other substances.

Answer:

Kelvin (K)

Explanation:

Recipe books suggest adding acidic ingredients like tomatoes, vinegar, or lemon juice to bitter foods to make them more palatable. The acidity helps to neutralize bitter flavors and enhances the dish's overall taste by adding a more acceptable sour taste.

The perception of bitterness in foods such as endives and Brussels sprouts is linked to the presence of certain compounds that can be indicative of toxic substances. The taste buds on the posterior tongue are especially sensitive to bitter tastes as a protective mechanism to induce the gag reflex to prevent the ingestion of potentially poisonous substances. To counteract the bitterness and make these foods more palatable, recipe books often recommend adding acidic ingredients like tomatoes, vinegar, or lemon juice. These acids can neutralize the bitterness to some extent and enhance the overall flavor profile of the dish by adding a sour element that is generally more acceptable to our taste palette.

Acids like citric acid found in lemon juice and acetic acid in vinegar are known to sour tastes which can help to balance or mask the bitter flavor. Moreover, acidic ingredients might also interact with volatile compounds that contribute to the bitterness, neutralizing them and making the food more enjoyable to eat.

Final answer:

The element with 99 electrons is Einsteinium (Es), and a mass number of 155 refers to the total number of protons and neutrons, indicating a specific isotope of Einsteinium with 56 neutrons.

Explanation:

The question asks about an element with a mass number of 155 and 99 for the number of electrons. Firstly, the number of electrons in an atom determines which element it is, as the number of electrons equals the number of protons in a neutral atom, known as the atomic number. With 99 electrons, we are referring to the element Einsteinium (Es), which is a synthetic element located in the actinide series of the periodic table.

The mass number mentioned, 155, typically refers to a specific isotope of an element, considering the mass number is the sum of the protons and neutrons within an atom's nucleus. Since Einsteinium has 99 protons (because it has 99 electrons), an isotope with a mass number of 155 would then have 56 neutrons (155 - 99 = 56).

It's also important to note that the mass number shown in parentheses on the periodic table represents the mass number of the most stable or most commonly occurring isotope for that element.

The correct answer to the question is option B. Compound

An element is a pure substance that can not be broken down into simpler substance.

A compound is a substance consisting of two or more elements chemically combined together.

Isotopes are atoms having the same atomic number but different mass number due to the difference in the neutron number of the atoms involved.

An ion is an atom or group of atoms which possess an electric charge.

The combination of carbon and oxygen will produce a compound. This is true because the carbon and oxygen will be chemically combined together as a new bond will be formed between them given rise to a new substance.

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Answer:

it is easy to change...

it allows scientists...

Explanation:

Answer:

a possible explanation or answer to a scientific question that is based on prior knowledge or research and is testable

chemical because batterys then eletrical becuase you turn on the car then mechanical

Answer:

1. B

3. C

4. its radioactive dating i learned about this

Metals have higher density than plastics. Hence they weigh more on small volume. Therefore a metal spoon has higher mass than a plastic spoon.

Density of an object is the measure of the mass per unit volume of the substance. It describes how closely its particles are packed in its volume. The density of a substance depends on the bond type,  pressure and temperature as well.

Metals are electropositive elements with greater densities. The metallic particles are held together by strong metal - metal bonds. This makes the metal lattice denser and hard.

Therefore, a metal spoon will have greater density and thereby mass in a given volume than plastic spoon which is of very less density compared to the metals.

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Answer:

The chlorophyll in a plants leaves absorbs light energy from the sun which is then later used to make glucose and oxygen. Consumers eat the plants to get nutrients. Consumers get their energy from the food they eat.

Explanation:

Hope this helps :)

Final answer:

Two physical properties that are useful for identifying a substance are its density and melting point. Density helps determine whether the substance will float or sink, while the melting point assists in distinguishing substances under controlled temperature conditions.

Explanation:

Two physical properties that can help you identify a substance are its density and melting point. Density is a measure of how much mass is contained in a given volume and can be particularly useful when determining whether a substance will float or sink when placed in a fluid.

The melting point—the temperature at which a substance changes from a solid to a liquid—can also be unique to a substance and is especially useful when comparing similar looking materials under controlled temperature conditions.

For example, pure water has a density of 1 gram per cubic centimeter at room temperature, and ice, which is solid water, will float in liquid water due to its lower density. The melting point of water is 0 degrees Celsius, which is a well-known physical constant.

On the other hand, substances like gold and silver have melting points of 1064 degrees Celsius and 961.8 degrees Celsius, respectively, and much higher densities, allowing for easy distinction from substances with similar appearance but different physical properties.

Final answer:

Electrolytes share the property of being able to conduct electricity when in solution because they dissociate into ions. Ions like sodium, potassium, and chloride are vital for body functions such as nerve transmission and water balance. Nonelectrolytes, which do not dissociate into ions, cannot conduct electricity.

Explanation:

All electrolytes have the common property of being able to conduct an electric current when dissolved in water or melted. This is because electrolytes are composed of ions, which are electrically charged particles. When these ions are in solution, they move towards electrodes of opposite charge, enabling the flow of electricity. For instance, when sodium, potassium, and chloride dissolve in water, they dissociate into Na+, K+, and Cl- ions, respectively. This dissociation into ions is what makes these substances electrolytic.

Sodium, potassium, and chloride are particularly important in the human body for their roles in nerve impulse conduction, muscle contractions, and regulating water balance. They, along with other cations like calcium and magnesium and anions such as bicarbonate, phosphate, sulfate, organic acids, and proteins, help maintain the body's ionic balance, acid-base balance, and osmotic pressure in bodily fluids. Electrolytes are crucial for maintaining life processes.

By contrast, nonelectrolytes do not dissociate into ions and therefore do not conduct electricity when dissolved or melted. Substances such as glucose and ethylene glycol are examples of nonelectrolytes.