135 g of aluminum initially at 400.°C is added to an unknown mass of water (initially at 25°C). When thermal equilibrium is reached, the system has a temperature of 80.°C. Find the mass of water. Note c = .89 J/g°C for Al

Answer:

B.

Explanation:

Most species that have lived on Earth are now extinct

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A P E X

The statement that best explains why so many fossils look different from the millions of species currently living on Earth is: B. Most species that have lived on earth are now extinct.

The fossil record is evidence that life on Earth has changed over time, with new species evolving and old ones going extinct. It shows the wide range of life that existed throughout Earth's history, including many species that no longer exist today.

The diversity of fossils is primarily due to the extensive range of species that have lived and gone extinct throughout the history of life on Earth.

Although some fossils may have changed over time or contain inaccuracies, they are still crucial for understanding the evolutionary relationships among different species.

Hence, option B is correct.

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Answer:

Answer the first ine made up of 2 or more.....

All mixtures are made up of two or more elements or compounds.

Compound is defined as a chemical substance made up of identical molecules containing atoms from more than one type of chemical element.

Molecule consisting atoms of only one element is not called compound.It is transformed into new substances during chemical reactions. There are four major types of compounds depending on chemical bonding present in them.They are:

1)Molecular compounds where in atoms are joined by covalent bonds.

2) ionic compounds where atoms are joined by ionic bond.

3)Inter-metallic compounds where atoms are held by metallic bonds

4) co-ordination complexes where atoms are held by co-ordinate bonds.

They have a unique chemical structure held together by chemical bonds Compounds have different properties as those of elements because when a compound is formed the properties of the substance are totally altered.

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Answer:

A. the average kinetic energy increases

Explanation:

temperature is a measure of the average kinetic energy of the particles in a sample of matter

Answer:

None

Explanation:

There are two S=O. bonds and two S-O bonds in sulfate ion lewis structure. Sulfur atom is the center atom and four oxygen atoms are located around sulfur atom. There are no lone pairs in the last shell of sulfur atom.

Ionic compound K₂O is potassium superoxide. CaCl₂ is calcium chloride. The compound Mg₃N₂ is magnesium nitride and NaClO is sodium hypochlorite and KNO₃ is potassium nitrate.

Ionic compounds are formed between metals and non-metals. They are bonded by lose of electrons from the metal to the non-metals. An ionic compound is named starting with the cation and then the anionic part is named second with the suffix "ide" , "ate" , "ite" etc.

The compounds with the general formula M₂O are called super oxides. K₂O is called potassium superoxide or dipotassium oxide.

The compound, CaCl₂ is named as calcium chloride. The subscripts in formula  are the number of each atoms in the compounds.

Similarly Mg₃N₂ is named as magnesium nitride and KNO₃ is called potassium nitrate. The compound NaClO is named as sodium hypochlorite.

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Answer:

86

Explanation:

According to the concept of percent yield, the percent yield of carbon dioxide is 72.51%.

Percent yield is defined as the ratio of actual yield to the theoretical yield multiplied by 100. If the actual and theoretical yield are same then the percent yield is 100%.If actual yield is less than the theoretical yield then the percent yield is less than 100%.Reason of this condition arising is the incompletion of reaction or loss of sample during recovery process.

In cases where percent yield is over 100% it indicates that more sample is recovered than the predicted amount.This condition arises when there are other simultaneous reactions taking place leading to the formation of product. It can also arise if there is incomplete removal of impurities from the sample .

In the given example, theoretical yield of carbon dioxide is as 32 g oxygen produces 44 g carbon dioxide,thus 32.5 g which is obtained by 2.5 moles of oxygen will require 32.5×44/32=44.68 g

Thus , on substitution in formula of percent yield, 32.4/44.68×100=72.51%.

Hence, the percent yield of carbon dioxide is 72.51%.

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Answer:

C) Stem helps in the conduction of water

Explanation:

It's the xylem and phloem present in the vascular bundles of stems that conduct water and minerals across the plant. Stems bear flowers and fruits in a position that facilitates the processes of pollination, fertilization, and dispersion of seeds. So, stem doesn't help in the conduction of water.

Answer:

the person above is correct

Explanation:

jjecjjeccejec hello good day?

Answer:

A. Stronger forces between particles means the substance boils at a higher temperature

Explanation:

Certain forces hold the atoms of different matter together. These forces of attraction between the atoms (basic particle of a substance), however, play a role in how difficult it is to break the substance. The stronger the force, the difficult it is to break the substance and vice versa.

In relation to temperature, a substance with stronger force will require more heat i.e higher temperature to break the atoms. Hence, Stronger forces between particles means the substance boils at a higher temperature. In other words, the stronger the force, the higher the boiling point of that substance and vice versa.

Answer:

then it is 5

Explanation:

because i said it is

Answer:

a

Explanation:

if the difference is over 1.7, an ionic bond will form

Answer and Explanation:

For each reaction, it is useful to detail which are the reactants (left side of the equation) and which are the products (right side of the equation), to deduce the chemical formulas.

1. Solid lithium reacts with water to produce hydrogen gas and a solution of lithium hydroxide.

Reactants: lithium element in solid-state (Li(s)) and water (H₂O) in the liquid-state. Products: hydrogen gas which is a diatomic molecule (H₂) and lithium hydroxide, which is a base formed by lithium cation Li⁺ and OH⁻ anion (LiOH).

Li(s) + H₂O(l) → H₂(g) + LiOH(aq)

2. Solid sodium reacts with gaseous chlorine to produce sodium chloride.

Reactants: sodium metal in solid-state (Na(s)) and chlorine which is a diatomic gas (Cl₂). Products: sodium chloride, which is a salt formed by sodium and chloride together (NaCl).

Na(s) + Cl₂(g) → NaCl(s)

3. Solid calcium carbonate breaks down into carbon dioxide gas, oxygen gas, and solid calcium.

It is a decomposition reaction, so we have only one reactant: calcium carbonate, which is a salt composed of carbonate anion (CO₃⁻²) and calcium ion (Ca²⁺). Products: carbon dioxide (CO₂), oxygen gas which is diatomic (O₂), and solid calcium (Ca(s)).

CaCO₃(s) → CO₂(g) + O₂(g) + Ca(s)

4. Solid iron(II) sulfate and a solution of barium chloride react to form solid barium sulfate and a solution of  iron (II) chloride.

Reactants: iron(II) sulfate which is an ionic compound formed by the sulfate ion (SO₄²⁻) and iron ion (with two positive charges: Fe²⁺), and barium chloride which is a salt of barium ion (Ba²⁺) and two chloride ions (Cl⁻). Products: the salts formed by ion exchange, barium sulfate (BaSO₄), and iron (II) chloride (FeCl₂).

FeSO₄(s) + BaCl₂(aq) → BaSO₄(s) + FeCl₂(aq)

5. Solutions of hydrochloric acid and sodium hydroxide react to produce liquid water with sodium chloride  dissolved in it.

It is the classical neutralization reaction. Reactants: hydrochloric acid (HCl) and the strong base sodium hydroxide (NaOH). Products: water (H₂O) and the salt formed by the anion provided by the acid (Cl⁻) and the cation provided by the base (Na⁺): NaCl.

HCl(aq) + NaOH(aq) → H₂O(l) + NaCl(aq)

Answer:

42g if CaO can be produced from 30g and 31.5g of CaO will be produced from 18g of O

Explanation:

40g of CA =56g

30g =×

cross multiple

=56*30/40

=42g

32g of O =56g

18g =×

cross multiple

=56*18/32

=31.5g

theoretical yield

42-31.5= 10.5

just guessing

Here is my answer. I hope this is helpful.

Answer:

1200g H20.

Explanation:

Write out the balanced equation... when an organic compound is burned, like C2H2, it is burned in oxygen (O2) and produces Water and Carbon Dioxide (CO2)

so 2C2H2 + 5O2  =  2H2O  + 4CO2

now that you have a balanced equation just convert to moles and solve

2000g C2H2 * 1mol C2H2 / 30gC2H2 * 2mol H2O/2mol C2H2 * 18gH2O/1molH20 = 1200g H20.

Answer:

C

Explanation:

The statement that best describes the influence that sexual reproduction has on genetic variation is as follows:

Thus, the correct option for this question is B.

Crossing over may be defined as a biological mechanism through which genetic material gets exchanged between the non-sister chromatids of the homologous chromosomes. The process of crossing over occurs in the Pachytene stage of mitosis.

Option C is incorrect because the process of crossing over never occurs between sister chromatids. So, it is eliminated. While options A and D are incorrect because they describe the mechanism of crossing over in the sense of meiosis which is absolutely incorrect.

Therefore,  the correct option for this question is B.

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Answer:

True

Explanation:

hope this helps:)))

Answer:

Correct: B

Explanation:

The first block wont move because:

Σf=3-3=0N.

The second block will move because:

Σf:5-3=2N (direction to the right).

The third block will move because:

Σf=3N (direction to the right).

Answer:

H2

Explanation:

H (or hydrogen), being a halogen, as an atom, has 7 valence electrons. This means that it naturally bonds with another atom of the same isotope in order to reach the desired total of valence electrons: 8.

So... H+H = H2. EZ

Answer:

its all of them

Explanation:

i just did it lol but just incase, "Molecules are made of two or more atoms that are chemically bonded together. The atoms can be of the same element or of different elements. Therefore, H2, CO2, SiO2, and NH3 are all molecules."

Answer:

net force is 100 N and direction is right

Explanation:

Explanation:

REFER TO THE ATTACHMENT ABOVE.....

Answer:

C

Explanation:

The answer is C as concentration is a major factor affecting the rate of reaction and it has a direct relationship with the rate of reaction.

The effect that the concentration of reactants has on the rate of a reaction is increasing the concentration increases the rate of the reaction. The correct option is C.

A reactant is a part of a reaction that is the first part of the reaction. Reactant can be more than one in the reaction. The different reactant reacts, and form a totally different product.

H2 + O2 = H2O

The hydrogen and oxygen are the reactants of the reaction.

Thus, the correct option is C. Increasing the concentration increases the rate of the reaction, as concentration plays a significant role in determining the rate of reaction and is directly related to it.

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Answer:

Chemistry has a reputation for being a complicated and boring science, but for the most part, that reputation is undeserved. Fireworks and explosions are based on chemistry, so it's definitely not a boring science. If you take classes in chemistry, you'll apply math and logic, which can make studying chemistry a challenge if you are weak in those areas. However, anyone can understand the basics of how things work, and that's the study of chemistry. In a nutshell, the importance of chemistry is that it explains the world around you.

Chemistry Explained

Cooking: Chemistry explains how food changes as you cook it, how it rots, how to preserve food, how your body uses the food you eat, and how ingredients interact to make food.

Cleaning: Part of the importance of chemistry is it explains how cleaning works. You use chemistry to help decide what cleaner is best for dishes, laundry, yourself, and your home. You use chemistry when you use bleaches and disinfectants, even ordinary soap and water. How do they work? That's chemistry.

Medicine: You need to understand basic chemistry so you can understand how vitamins, supplements, and drugs can help or harm you. Part of the importance of chemistry lies in developing and testing new medical treatments and medicines.

Environmental Issues: Chemistry is at the heart of environmental issues. What makes one chemical a nutrient and another chemical a pollutant? How can you clean up the environment? What processes can produce the things you need without harming the environment?

We humans are all chemists. We use chemicals every day and perform chemical reactions without thinking much about them. Chemistry is important because everything you do is chemistry! Even your body is made of chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter is made of chemicals, so the importance of chemistry is that it's the study of everything.

Importance of Taking Chemistry

Everyone can and should understand basic chemistry, but it may be important for you to take a course in chemistry or even make a career out of it. It's important to understand chemistry if you are studying any of the sciences because all of the sciences involve matter and the interactions between types of matter.

Students wanting to become doctors, nurses, physicists, nutritionists, geologists, pharmacists, and (of course) chemists all study chemistry. You might want to make a career out of chemistry because chemistry-related jobs are plentiful and high-paying. The importance of chemistry won't be diminished over time, so it will remain a promising career path.

Paragraph 1:

Chemistry is important Because it is so fundamental to our world, chemistry plays a role in everyone's lives and touches almost every aspect of our existence in some way.

Paragraph 2:

Chemistry is essential for meeting our basic needs of food, clothing, shelter, health, energy, and clean air, water, and soil.

Paragraph 3:

Even your body is made of chemicals. Chemical reactions occur when you breathe, eat, or just sit there reading. All matter is made of chemicals, so the importance of chemistry is that it's the study of everything.

Paragraph 4:

Chemistry has a reputation for being a complicated and boring science, but for the most part, that reputation is undeserved.

Paragraph 5:

Fireworks and explosions are based on chemistry, so it's definitely not a boring science. If you take classes in chemistry, you'll apply math and logic, which can make studying chemistry a challenge if you are weak in those areas.

Hope it helps :))

Answer:

each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.

Explanation:

Ammonia gas is a compound that is made up of two elements, nitrogen and hydrogen. So, option C is right.

A compound is a substance that is made up of two or more elements chemically combined. Ammonia gas is made up of the elements nitrogen and hydrogen, which are chemically combined in the ratio of 1:3.

Elements are the basic building blocks of matter. They cannot be broken down into simpler substances by chemical means. Atoms are the smallest unit of an element that can exist.

Mixtures are substances that are made up of two or more elements or compounds that are not chemically combined. The components of a mixture can be separated by physical means, such as filtration or distillation.

An atom is the smallest unit of an element that can exist and ammonia gas is not an atom because it is not the smallest unit of an element.

Therefore, option C, compound is correct.

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Answer: Rutherford's model was the first propose of the existence of small, dense nucleus's.

Explanation: The atom, as described by Ernest Rutherford, has a tiny, massive core called the nucleus. The nucleus has a positive charge. Electrons are particles with a negative charge. Electrons orbit the nucleus. The empty space between the nucleus and the electrons takes up most of the volume of the atom.

Answer: Here is the correct image of the first atomic model it's in the picture!

Explanation: I did it on USA Test Prep to see which one is right

Answer:

Malleable

Explanation: