Which one is a true statement about exothermic reactions?

A. Energy from an outside source is continuously being added
B. The reaction container always feels cold
C. The reactants have more heat energy than the products
D. More heat is given off then is put into the reaction

the answer is guyots

Answer:

The correct answer is "sediment".

Explanation:

A sediment is defined as a solid material that settles down to the bottom of a liquid. Sand grains, pebbles, mud, shells, and leaves are all examples of sediment. The size of a sediment variables from small particles that could be of 2 millimeters (in the case of sand grains), to particles as large as 250 millimeters (in materials such as cobble).

Answer: D. experimental bias

Explanation:

An experimental bias is the condition in which the experimenter manipulate the experimental procedure, equipment and even the results so as to obtain the desired outcome.

The given situation is an example of experimental bias this is because of the fact that field A was supplied with old fertilizers and brand new irrigation system but field B was supplied with new fertilizers and irrigation system which will be repaired in next season. Hence, a experimental bias is done so as to show that the old fertilizer is better than the new one.    

Final answer:

The solubility of KCl in ethanol is 0.25 g/100 mL at 25°C. Compared to the solubility of KCl in water, KCl is much more soluble in water than in ethanol.

Explanation:

The solubility of KCl in ethanol is 0.25 g/100 mL at 25°C. This means that at this temperature, 0.25 grams of KCl can dissolve in 100 mL of ethanol. Comparing this to the solubility of KCl in water, we can see that the solubility of KCl in water is generally much higher. While the solubility of KCl in ethanol is 0.25 g/100 mL, the solubility of KCl in pure water at 25°C is 27.8 g/100 mL. Therefore, KCl is much more soluble in water than in ethanol.

Geologists use index fossils for dating of rock layers

Geologists use index fossils to determine the age of rocks. Index fossils are also known as key fossils; they define dating of rock layers.

Some of the characteristics of fossil index include:

Index fossils are defined as “commonly found” because they are widespread but limited in a period of time. If an index fossil is found in a particular layer, the layer will determine the age of the layer, therefore with the use of index fossils, one can easily define the geological periods. In many cases, the geological periods can last as far as tens of millions of years.

Index fossils have a very short life span, therefore the age at which they are found defines their age. They are used to determine the period and eras of the geological time scale.

Geological time scale is also known as GTS, it refers to a system of dating which relates stratigraphy to time. Geological time scale is used by Geologists to determine the period and the relationship of events that have taken place in the history of the earth.

Therefore, Geologists use index fossils for dating of rock layers

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KEYWORDS:

Geologists use index fossils for dating rock layers. The correct answer is option A.

An index fossil is a fossil that is known to have lived during a specific geologic time period. By identifying the index fossils in a rock layer, geologists can determine the age of the rock layer.

Index fossils are used because they are widespread, abundant, and have a short geologic range. This means that they are found in many different locations, are common in the fossil record, and only existed for a relatively short period of time.

In conclusion, to date rock layers, geologist use index fossil.Option A is the correct answer.

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The reason the metals are malleable, is because they have mobile electrons in their s orbitals.

The ions create a lattice-like structure held together by the metallic connections. Metallic bonds are what allow metals to flex without breaking and conduct electricity.

Chemical bonds known as metallic bonds are produced by the electrostatic attraction of positively charged metal ions and conduction electrons. The sharing of free electrons among a structure of positively charged ions could be used to characterize it.

Metal atoms form metallic connections. Ionic bonds link metals to non-metals, whereas metallic bonds link many metal atoms. Metallic bonding can be observed in action on copper wires and sheets of aluminum foil.

When the charge is dispersed over a broader area than the size of a single atom in a solid, metallic bonds are created. Most left-handed elements in the periodic table form metallic bonds.

Thus, Metallic bonds are what allow metals to flex without breaking and conduct electricity.

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Final answer:

To find the volume of 1.25 M H₂SO₄ solution needed for 36 grams of H₂SO₄, calculate the moles of H₂SO₄ and divide by the molarity. Martha should use approximately 294 ml of the solution.

Explanation:

To determine the volume of 1.25 M H₂SO₄ solution Martha should use to obtain 36 grams of H₂SO₄, we must first calculate the number of moles of H₂SO₄ in 36 grams.

The molar mass of H₂SO₄ is (2×1.01) + 32.07 + (4×16) = 98.09 g/mol. Therefore, the number of moles of H₂SO₄ is:

Number of moles = Mass / Molar mass
Number of moles = 36 g / 98.09 g/mol
Number of moles ≈ 0.367 mol

Next, we use the molarity of the solution to find the volume needed:

Molarity (M) = Moles of solute / Volume of solution in liters (L)

Therefore, Volume of solution = Moles of solute / Molarity
Volume of solution = 0.367 mol / 1.25 M
Volume of solution ≈ 0.294 L

Finally, to convert liters to milliliters we multiply by 1000 ml/L:

Volume of solution ≈ 0.294 L × 1000 ml/L = 294 ml

Martha should use approximately 294 ml of the 1.25 M H₂SO₄ solution to get 36 grams of H₂SO₄.

You must first convert the supplied value to moles because the molar mass of cadmium is 112.41 grams. Divide 3 grams by the molar mass of 112.41 grams to accomplish that. Consequently, there are 1.601022 cadmium atoms in a 3.00 gram of cadmium.

Using the periodic chart, calculate the element's molar mass. Divide the given mass in grams by the molar mass to get the number of moles.

Multiply the number of moles by Avogadro's number to obtain the total number of atoms.

The amount of units in one mole of any substance is known as Avogadro's number, and it is equal to 6.02214076 1023.

Depending on the substance and the nature of the reaction, the units may be electrons, atoms, ions, or molecules (if any).

Therefore, 3.00g of cadmium contain 1.60×1022 atoms.

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To find the number of atoms of cadmium in 3.00 grams, divide the mass by the molar mass of cadmium to get moles and then multiply by Avogadro's number. The calculation reveals there are approximately 1.61 x 10²² atoms of Cd in 3.00 grams.

To determine how many atoms of cadmium (Cd) are in 3.00 grams of cadmium, we use Avogadro's number and the molar mass of cadmium. The first step is to find the number of moles of cadmium in 3.00 grams.

Calculate the number of moles of cadmium: Number of moles = mass (in grams) / molar mass (in grams per mole). The molar mass of cadmium is approximately 112.411 g/mol.

Multiply the number of moles by Avogadro's number (6.022 x 10²³ atoms/mol) to obtain the number of atoms.

Here's the calculation:

Number of moles = 3.00 g / 112.411 g/mol = 0.0267 mol

Number of atoms = 0.0267 mol x 6.022 x 10²³ atoms/mol = 1.61 x 10²² atoms of Cd

To solve such this we must know the concept of double displacement reaction. Therefore, the mass of oxygen is 27.2g when 20.4g of magnesium react with 34.0g of magnesium oxide.

Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.

The balanced reaction is

2Mg+ O [tex]_2[/tex][tex]\rightarrow[/tex]2MgO

mass of Magnesium =20.4g

Molar mass of magnesium =24gmol

moles of magnesium =0.85moles

moles of magnesium = moles of oxygen =0.85moles

Mass of oxygen =Molar mass of oxygen ×moles of oxygen

                           =32g/mol×0.85moles

                          =27.2g

Therefore, the mass of oxygen is 27.2g.

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Its not D, im not quite sure but if you have to guess then choose ab or c

C. Is your Answer (Solute)

Took The Test

Animal

Explanation:

e  e e e e  e e e e e e e e e e  e e e.

Answer:

Barium

Got this on a test and got it right! :)

For ages 14-18, young adult romance novels are popular, often blending aspects of realism and romanticism. Examples include books like 'Twilight', 'The Fault in Our Stars', and 'Divergent'. These novels provide relatable plots and characters while offering an escape into various genres like fantasy, mystery, and dystopian fiction.

Teenagers between the ages of 14-18 often lean towards young adult romance novels that incorporate elements of fantasy, mystery, and realism. Two popular categories of stories that these novels might follow are romance and the bildungsroman, a genre focusing on the growth of its main character, fitting given the phase of life teenagers are in.

For example, 'Twilight' by Stephenie Meyer that offers a blend of romance and fantasy with the main characters being a teenage girl and a vampire, set in contemporary times. Other examples are 'The Fault in Our Stars' by John Green, a poignant love story between two teenagers met at a cancer support group, and 'Divergent' by Veronica Roth that blends romance with dystopian fiction.

The beauty of these novels is they take variations from the type of normal life (romanticism) and incorporate them into real life settings (realism). These stories provide young readers an escape from their day-to-day lives, while also offering relatable plots and characters that they can connect with on a personal level. Regardless of whether the novels have elements like magic, vampires, or talking animals, the primary focus rests on the exploration of human emotions, friendships, and romances, imparting a sense of both imagination and reality.

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When an article is in motion then the measure of energy stored in it is called kinetic energy.

       [tex]\text{Kinetic}\; \text{Energy} &= \dfrac{1}{2}\; \text{mv}^{2}[/tex]

       where, m = mass of the article in kg

       v = velocity in  [tex]\dfrac{\text{meter}}{\text{seconds}}[/tex]

Therefore, the kinetic energy is directly proportional to the temperature.

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Mendeleev organized his Periodic Table by increasing atomic mass in the same way that today's Periodic Table is organized by atomic number.

A periodic table, also known as an elemental periodic table, is a tabular representation of the chemical elements.

It is widely used in chemistry, physics, and other sciences, and is widely regarded as a chemistry icon.

Mendeleev positioned elements in rows in his periodic table by increasing atomic mass.

Elements with lower atomic masses were located on the left within a row.

Every time the chemical characteristics of the elements repeated, Mendeleev began a new row. As a result, all of the elements in a column shared the same properties.

Because of the arrangement of the elements, it is known as the periodic table.

Thus, the he arranged it by increasing atomic mass.

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Final answer:

Dmitri Mendeleev organized the original Periodic Table by atomic mass and predicted undiscovered elements by leaving gaps for them, differing from the modern table's organization by atomic number.

Explanation:

The Russian chemist Dmitri Mendeleev organized his Periodic Table by atomic mass, unlike the modern Periodic Table which is organized by atomic number. He encountered a challenge where he had to list some elements out of order of their atomic masses to align them with others of similar chemical properties. Mendeleev was developing a chemistry textbook for his students and needed a logical way to present the known elements.

During this process, Mendeleev left gaps in his Periodic Table to maintain the grouping of chemically similar elements, predicting the existence of undiscovered elements that would fit into these gaps. These gaps provided the periodic table with a predictive value which was validated when elements like gallium, scandium, and germanium were discovered with properties closely matching his predictions.

Answer: Only energy can enter or exit a closed system

Explanation: Apex

The mass and energy in a closed system did not change, it conserved. In a  reaction, the mass of the reactant will be equal to the mass of the product.

A closed system is a thermodynamic system, in which there is no transfer of energy and mass with the outer environment. There is no change in a system to take place.

Thus, the mass and energy in a closed system did not change, it conserved. In a  reaction, the mass of the reactant will be equal to the mass of the product.

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Answer:

Valence Electrons is the answer.

Explanation:

Valence electrons are the outermost shell of electrons in an atom. The valence electrons determine the reactivity to chemical reactions an atom has. This is because those with the same number of valence electrons have similar chemical properties. It is also why elements with the same number of valence electrons are put in the same group on the periodic table.

The reactivity of an atom is determined by the number of valence electrons it has.

Valence electrons are the electrons found in the outermost energy level of an atom. These little particles called electrons are very important in how chemicals react and stick together.

Atoms with not enough electrons in their outermost shell (called valence shell) are more likely to react with other atoms. These tiny particles called atoms want to gain, lose, or share electrons so that they can have a stable arrangement with complete outer shells.

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The answer is actually False.

Answer:

FALSE

Explanation:

I got the question correct.

Answer:

Six thousand

Explanation:

The Ussher sequence is a seventeenth century order of the historical backdrop of the world detailed from a strict perusing of the Old Testament by James Ussher, the Archbishop of Armagh.  

Priest James Ussher, a 17th-century Anglican pastor and scriptural researcher had the appropriate response. aaccording to him, in a 1658 sequence titled The Annals of the World, God made the world on October 23, 4004 BCE which accounts for 6000 years for the age of the earth.

The people of chungungo need to use nets to catch moisture in the air to capture the water droplets present in the environment and collect the water for various uses.

The moisture in the air is the tiny water droplets that are present in the environment or in the air it is mostly present in the cold zone of the environment.

The chungungo is a desert coast area and their is lot of the shortage of the water in their areas and the chances of rain is very low so the people of there use the net to capture the water drops from the air.

Therefore, people of chungungo need to use nets to catch moisture in the air to capture the water droplets present in the environment and collect the water for various uses.

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Final answer:

The people of Chungungo use nets to capture moisture from the air due to limited fresh water sources in their region. This technique is a form of atmospheric water collection and has historical precedence dating back to the Old Stone Age.

Explanation:

The people of Chungungo needed to use nets to catch moisture in the air because they inhabit an area with limited access to fresh water. This innovative method allows them to collect water from fog and mist, which is especially valuable in arid or semi-arid regions where rainfall is scarce. Using nets as a form of atmospheric water collection is an ancient technique with roots tracing back to the Old Stone Age, as evidenced by archaeological findings similar to the limestone “sinkers” from the Maedun cave in South Korea, which date to 27,000 BC. These sinkers were tied to nets to catch small fish in streams, showcasing the long history of using nets for various forms of capturing and harnessing natural resources.

The coefficients balance the equation with respect to the law of conservation of mass.

So, from this, we can conclude that the coefficients balance the equation with respect to the law of conservation of mass.

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Mixture is homogeneous in case when lemon juice is filtered. But if it is not properly filtered and contains pulp or seed then the resultant mixture would be the heterogeneous.

Mixture are created using two or more chemical substances. If all the substances in the mixture are in the same phase then it would be a homogeneous mixture else if two substances that differ in a phase from the mixture it is a heterogeneous mixture.

For example freshly squeezed lemon juice, water and mixture of a sugar is homogeneous when lemon is properly filtered because all are present in a same phase.

When Sherry combined water, lemon juice, and sugar in a pitcher, she created a homogeneous mixture, a combination of substances that are uniformly mixed together.

Sherry has made a homogeneous mixture when she combined water, lemon juice, and sugar in a pitcher. A homogeneous mixture, also known as a solution, is a combination of substances with a composition that is uniform throughout. For example, when sugar is stirred into a glass of water, it dissolves in the water and the sugar molecules are evenly distributed throughout the mixture, making it homogeneous. In contrast, a heterogeneous mixture is a combination of substances whose composition can vary from point to point because the substances do not thoroughly mix; an example would be oil and vinegar salad dressing.

A homogeneous mixture is a combination of substances with a composition that is uniform throughout. Sherry's combination of water, lemon juice, and sugar in a pitcher would be considered a homogeneous mixture because the components are evenly distributed and the mixture appears uniform.

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The statement is true; models are used to represent complex systems that are difficult to study directly, such as subatomic particles or large-scale environmental processes.

Making models involves creating representations of complex objects or processes to help people study and understand things that cannot be observed directly. The correct answer to the student's question is A. True.

Scientific models are simplified versions of a part of the real world that help us understand, analyze, and predict behaviors of complex systems. These models can take the form of physical constructions, mathematical equations, computer programs, or simulations. For instance, atomic models allow us to visualize and understand the structure of an atom, even though atoms are far too small to be seen with the bare eye.

Models are particularly beneficial in fields like physics, where phenomena at very small scales or very high speeds occur, which are beyond human perception. However, it is essential to acknowledge that models are approximations and are not as detailed as the real phenomena they represent, and it's important to understand their limitations.

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