What is the main function of the circulatory system in multicellular organisms? A. to bring oxygen into the lung B. to put carbon dioxide into all blood vessels C. to expel waste products from the body D. to transport materials throughout the body

Elements are the simplest substances in nature that cannot be broken down into smaller parts by normal chemical means. They contain only atoms of the same type, ones that have identical chemical properties. There are at least 90 naturally-occurring elements, plus man-made ones. If you look at a periodic table, you'll see the names of each of these elements and some of their properties (such as mass, or how heavy the atom is).

Molecules & Compounds

When atoms from different elements are joined together in groups, they form molecules. The atoms in molecules bind together chemically, which means that the atoms cannot be separated again by physical means, such as filtration. The molecule has different properties from the elements from which is was made. A water molecule is not three separate atoms, two hydrogen (H) and one oxygen (O), but it is actually a unique H2O molecule with its own set of distinct properties.

Like elements that are formed of atoms of the same sort, compounds are formed of molecules of the same sort. The elements can be combined into about 2 million different compounds! Did you know that eggshells are made up of a calcium carbonate compound? And citric acid, which is found in oranges and other citrus fruit, is a compound of carbon, hydrogen, and oxygen atoms. Your kids might find it helpful to do a science research project finding other common compounds around your house. Make hypotheses and do research using a chemistry reference book, web site, or text book to find out the answers.

There are more carbon compounds than compounds of any other element. Organic compound is the name for the carbon compounds found in all living things.

Mixtures - A Bit of This and That

All matter can be classified into two categories: pure substances and mixtures. A pure substance consists of a single element or compound. Iron is formed only of iron (Fe) atoms; table salt is formed only of sodium chloride (NaCl) molecules. A mixture, however, is made up of different compounds and/or elements. When salt is added to water to make saltwater, it becomes a mixture. The salt and water molecules do not combine to form new molecules, but only "mix" together while still retaining their identities. Air is also a mixture, containing just the right amounts of nitrogen, oxygen, and other gases for life on Earth.  

Not all mixtures have the same composition throughout. Salt water does, but Italian salad dressing does not--the parts separate and are not perfectly blended or homogenous. Mixtures of metals are called alloys (bronze is an alloy of copper and tin); liquid mixtures (such as saltwater) are called solutions.

The substances that make up a mixture can be separated by physical means because they have different physical properties (such as different melting points) and are not chemically bonded. A mixture can be separated into its parts in a variety of ways, including decantation (letting the sand in a mixture of water and sand settle, and then draining off the water, for example), filtering, and evaporation. You can use a kitchen funnel and coffee filter for filtration, and either use sunlight or low heat for evaporation. Try out these methods on saltwater and a sand and water mixture to see how they work and compare the results. Evaporation will work for both saltwater and sand and water solutions, but filtration will not work for saltwater. Can you think of other examples where a separating method will work for one mixture and not another? Another one to try is lemon juice, a mixture of water and citric acid; what do you think happens when it is boiled? The water evaporates and eventually leaves nothing but citric acid crystals

A small set of elements combine in whole number ratios to form compounds with specific compositions, like glucose or water. Molecules are the smallest particles in compounds with consistent ratios of atoms. Mixtures, on the other hand, involve physical combinations of substances without fixed proportions.

How Elements Combine to Form Molecules, Compounds, and Mixtures

Atoms of different elements can combine in simple whole number ratios to form chemical compounds. These compounds have a specific composition and possess unique chemical and physical properties that distinguish them from other compounds. For instance, glucose, an essential body fuel, always consists of carbon, hydrogen, and oxygen in a fixed ratio: six carbon atoms, twelve hydrogen atoms, and six oxygen atoms.

Two or more atoms join together to create a molecule, which is the smallest unit of a substance retaining its distinctive properties. A common example is a molecule of water, which is consistently made up of one oxygen atom and two hydrogen atoms, represented by the chemical formula H₂O. The consistent composition of a compound is represented by its chemical formula, indicating the fixed proportion of each element within it.

Apart from forming compounds, elements and compounds can also fabricate various mixtures. Mixtures are combinations of two or more substances that can be separated by physical means. In contrast to compounds, the components in a mixture do not combine in a fixed ratio.

In our daily lives, the elements from the periodic table combine in countless ways to form the compounds and mixtures we use every day, from the water we drink to the air we breathe, and the myriad of products we come into contact with.

The described crumbly, weak, red-brown metal is likely to be copper or copper(II) oxide if in a degraded state. Metals like copper are generally shiny, ductile, malleable, and conduct electricity and heat well due to the sea of delocalized electrons in their structure.

The solid described as crumbly, weak, red-brown, and probably a metal as found on the periodic table is likely to be copper. Copper is a metal that is malleable and ductile and is known for its red-brown color. However, if the metal is weak and crumbly, it may have oxidized to form copper(II) oxide (CuO), which is not as strong as metallic copper. This could happen due to exposure to elements like air or moisture over time.

Overall, metals are generally hard, opaque, shiny, and have good electrical and thermal conductivity. They are most often found on the left side and towards the middle of the periodic table. The properties of metallic solids like copper can include a high degree of malleability and good electrical conductivity due to the sea of delocalized electrons within their structure.

Answer:

is held in genetic material called DNA.

Explanation:

:)

Answer:

1.- Oldest rock in the Earth

2.- Rocks of the moon

3.- Rocks of the meteorites

Explanation:

1.- In our Earth, there has been different studies that show the age of different layers in our planet by radiation, in this way, we can imagine how has been changing the surface trough this millions of years.

2.- By sonic sounds, the rocks of the moon can be analyze to calculate it relative age, and how this is corresponding to the age of our planet.

3.- Finally, another evidence of our Earth age, is by comparing the mass of different space bodies with our planet.

Hope this info is useful.

Answer:

The study of rocks, especially sedimentary rocks that formed underwater but are no longer underwater, is the primary source of information about the earth's age. The second line of geological evidence that the earth might be very old came from fossils. And finally, examining radioactive elements and estimating the age of rocks using certain rates of radioactive element decay is a third line of geological evidence for the age of the Earth.

Explanation:

Earth's rotation sets up a general circulation pattern from the poles to the equator. Uneven heating breaks it into six cells and deflects the surface winds.

or

Uneven heating sets up a general circulation pattern from the poles to the equator. Earth''s rotation breaks it into six cells and deflects the surface winds.

Intrusive rocks have large mineral crystals

Most igneous rocks that formed from magma have small mineral crystals but intrusive rocks have comparatively larger crystals. Intrusive igneous rocks cool from magma slowly because they are buried beneath the surface, so they have large crystals. A common example is the granite which is an igneous rock that is composed of four minerals. These minerals are quartz, feldspar, mica, and usually hornblende and its crystals are big in size.

Answer is: mass.

Mass is a fundamental measure of the amount of matter in the object.  Kilogram (symbol: kg) is the base unit of mass in the International System of Units.  

The weight is the force of gravity on the matter.  It is affected by gravity.

Volume is the amount of space that a substance occupies.  It is affected by temperature.

Density is a measure of mass per unit of volume (for example grams per milliliter). It is affected by temperature.

The hot plate continually adds heat energy to the water, increasing the kinetic energy of water molecules. This results in accelerated molecular motion, often leading to a state change if sufficient energy is added.

The hot plate is an example of an external source of energy that continually adds heat energy into the water system. This additional energy causes the water molecules to increase their motion. Essentially, the water molecules absorb the heat energy, which increases their kinetic energy. The result is a state of accelerated molecular motion, often leading to a phase change from liquid to gas, assuming sufficient energy is added. This scenario essentially demonstrates the concept of thermal energy transfer and the effect of heat on molecular motion.

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Final answer:

The statements provided are related to genetics, the science of heredity and variation in living organisms. The true statements affirm that traits are passed on by genes, different genes control different traits, gametes have half the number of chromosomes as body cells, and a human gamete has 23 single chromosomes. A false statement is that a body cell and a sex cell have the same number of chromosomes.

Explanation:

True or False:

Traits are passed on by genes. TRUEDifferent genes control different traits. TRUEA body cell and a sex cell have the same number of chromosomes. FALSEGametes have half the number of chromosomes of body cells. TRUEA human gamete has 23 single chromosomes. TRUE

The subject of these questions is genetics, which is a key topic within biology. These statements address the fundamental concepts of heredity and chromosome behavior during the formation of gametes. Genes, located on chromosomes, are the heritable units that carry information for traits. Gametes, which are sex cells like the egg and sperm in humans, have half the number of chromosomes compared to somatic or body cells, ensuring that when two gametes merge at fertilization, the resultant cell has the correct diploid number of chromosomes. In humans, this diploid number is 46, with gametes having 23.

a source of energy

Answer: a source of energy

Explanation: Because it is right

Final answer:

Explanation of how to balance the chemical equation C₆H₅Cl + O₂ → CO + 2H₂O + HCl in a detailed manner.

Explanation:

The balanced equation:

C₆H₅Cl + 5O₂ → 6CO + 2H₂O + 2HCl

In this balanced chemical equation, each type of atom is balanced on both sides of the reaction by adjusting the coefficients of the compounds. For example, to balance the carbons, 6CO is needed on the product side. Also, 5 oxygen molecules are needed to balance the oxygen atoms.

Explanation:

Neptunists: They believed that the rocks on the Earth were formed by crystallization of various minerals found in the early Earth's oceans. The theory of Neptunism was proposed by Abraham Werner in later part of 18th century.

In contrast to Neptunists, Plutonists (also known as Volacanists) believed that the rocks on the Earth were formed through magmatic or volcanic activity. These rocks then passed through a repeated cycling of deposition, weathering away, getting deposited at the sea bed and rising again. The theory of Putonism was proposed by Anton Moro in 1750.

Answer:

sugar i took the test

Explanation:

Answer:

It's sugar

Explanation:

I took the test, the answer is sugar and its not the rest of the choices because they all have something mixed with them, AKA not pure.

Approximately 1.57 grams of sodium (Na) and 4.82 grams of chlorine (Cl2) are needed to produce 4 grams of table salt (NaCl). This is based on the molar mass of the compounds and the stoichiometry of the balanced chemical equation.

To produce 4 grams of table salt, NaCl, the first step is to determine the number of moles in 4 grams of salt. Knowing that the molar mass of NaCl is 58.44 g/mol, we can do so by dividing the mass of the salt by its molar mass (4 g / 58.44 g/mol), giving us approximately 0.068 moles of NaCl.

Since the balanced chemical equation for the reaction is 2Na + Cl2 --> 2NaCl, it follows that the molar ratio between NaCl and Na is 1:1. Therefore, we need 0.068 moles of sodium (Na) to produce 4 grams of NaCl. Given that the atomic mass of Na is 23 g/mol, we multiply 0.068 moles by 23 g/mol to find that approximately 1.57 grams of sodium are needed.

For chlorine gas (Cl2), the molar ratio with NaCl is also 1:1. So, we need 0.068 moles of Cl2 as well. Given that the molar mass of Cl2 is 35.45 g/mol * 2 (since it's diatomic), we multiply 0.068 moles by 70.9 g/mol to find that approximately 4.82 grams of chlorine are needed. Therefore, it takes approximately 1.57 grams of sodium and 4.82 grams of chlorine to produce 4 grams of table salt.

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Answer is: B.)The velocity of a car reduced from 50 km/h over one minute.

Ending velocity is defined as the velocity attained by a body after completing distance at certain time interval:

v(ending velocity) = v(initial velocity) + a·t.

a is acceleration attained by the body (in this examle car).

t is time (in this example one minute).

Because velocity is reduced, acceleration has negative sign.

An car average acceleration over a period of time is its change in velocity.

Answer: B

Explanation:

Progress Learning

Matter is anything that occupies space and has mass, and it can exist in various forms. Examples of matter include solids, liquids, and gases, which all have different properties. Matter can be found in everyday items like books, computers, food, and dirt.

Matter is defined as anything that occupies space and has mass. Solids, liquids, and gases are all examples of matter. Solids, such as a book or a computer, have a fixed shape and volume. Liquids, like water or juice, have a fixed volume but take the shape of their container. Gases, such as air, have neither a fixed shape nor volume. Other examples of matter include food, like an apple or a slice of bread, and dirt or soil. These examples demonstrate how matter can come in a variety of forms and can be found in our everyday lives.

It exists in various forms, and the three main states of matter are solids, liquids, and gases, each with distinct properties:

Solids: Have a definite shape and volume. The particles in a solid are closely packed and vibrate in fixed positions.

Liquids: Have a definite volume but take the shape of their container. The particles in a liquid are more loosely packed than in a solid and can move past each other.

Gases: Have neither a definite shape nor volume. The particles in a gas are widely spaced and move freely.

Additionally, matter can undergo phase changes, transitioning between these states under different conditions (e.g., melting, freezing, boiling).

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Answer : Cells cannot be as large as a cube because of the surface area to the volume ratio gets smaller as the cell size gets larger. So, if the cell grows beyond a certain limit, the cell contents will not be able to cross the cellular membrane that fast, to accommodate the increased cellular volume.

Also, cells are so small in size, so that they can maximize their ratio of surface area to volume. In that case, smaller cells will have a higher ratio which will allow more molecules and ions move across the cellular membrane per unit of cytoplasmic volume.

Therefore, cells are so small in size as they need to be quick to get the nutrients in and throw the waste out.

the answer is B decrease I know this because I already did the test.

According to the laws of motion when a spacecraft is flying away from the moon toward earth.The moons gravitational pull on the spacecraft will decrease.

Motion is defined as a phenomenon which is described with respect to change in object's position with respect to time.It is given in terms of displacement,velocity,distance ,acceleration,speed.

Branch of physics which deals with motion of objects without any reference to it's cause is called kinematics while the branch which studies forces and their effects on motion is called as dynamics.

Motion applies to various systems like objects,bodies, matter particles ,radiation ,curvature.There are three laws of motion which are proposed by Newton.Classical mechanics is based on Newton's law of motion.Relativistic  mechanics is based on modern kinematics.

Learn more about motion,here:

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