which of the following formulas represent a covalent molecule?
A)CaS
B)Co2
C)Na2O
D)FeCl3

The reaction occurs via a nucleophilic substitution mechanism. The D_2O molecule acts as the nucleophile, attacking the carbon atom of the CH_3CH_2OBH_3 molecule.

Step 1:

NaBH_4 + CH_3CH_2OH → CH_3CH_2OBH_3 + NaOH

Step 2:

CH_3CH_2OBH_3 + D_2O → CH_3CH_2OD + BH_3OH

Step by explanation in  detail

Step 1:

NaBH_4 + CH_3CH_2OH → CH_3CH_2OBH_3 + NaOH

The reaction occurs via a nucleophilic substitution mechanism. The Na^+ cation acts as a spectator ion and does not take part in the reaction. The BH_4- anion acts as the nucleophile, attacking the carbon atom of the CH_3CH_2OH molecule. This causes the C-O bond to break and the BH_3 group to form a bond with the carbon atom. This results in the formation of the CH_3CH_2OBH_3 molecule and the NaOH molecule.

Step 2:

CH_3CH_2OBH_3 + D_2O → CH_3CH_2OD + BH_3OH

The reaction occurs via a nucleophilic substitution mechanism. The D_2O molecule acts as the nucleophile, attacking the carbon atom of the CH_3CH_2OBH_3 molecule. This causes the C-B bond to break and the D atom to form a bond with the carbon atom. This results in the formation of the CH_3CH_2OD molecule and the BH_3OH molecule.

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Answer:

36 grams

Explanation:

Answer:

When making ice cream, you're using physical changes. When you shake your bag, you're freezing the milk, which means the water in it is turning from a liquid (water) into a solid (ice).

Answer:

2 Cr(s) + 3 Fe(NO3)2(aq) = 3 Fe(s) + 2 Cr(NO3)3(aq)

Explanation:

I balanced this chemical equation so that both sides are equal, meaning that the mass of reactants is equal to mass of products.

0.002 liters of 225 M Na2S solution is required to completely react with 81.8 g Fe(C2H3O2)3

Starting from the balanced equation of the reaction and the molar mass of iron (III) acetate (Fe(C2H3O2)3, first the reacting moles of this compound are determined, then the amount of reacting moles of sodium sulfide (Na2S) is determined and finally the amount of solution that contains said amount of moles.

3Na2S + 2Fe(C2H3O2)3 → 6NaC2H3O2 + Fe2S3

This determination is made in three steps:

If 233.00 g of Fe(C2H3O2)3 is equivalent to 1 mol of Fe(C2H3O2)3

So 81. 8 g Fe(C2H3O2)3 equals x mol of Fe(C2H3O2)3

X mol of Fe(C2H3O2)3 = 81. 8 g Fe(C2H3O2)3 x 1 mol of Fe(C2H3O2)3 / 233.00 g of Fe(C2H3O2)3

X mol of Fe(C2H3O2)3 = 0.351 mol

If 2 moles of Fe(C2H3O2)3 react with 3 moles of Na2S

Then 0.351 mol of Fe(C2H3O2)3 reacts with x mol of Na2S

X mol of Na2S = 0.351 mol Fe(C2H3O2)3 x 3 mol of Na2S / 2 mol of Fe(C2H3O2)3 = 0.526 mol

If there are 225 moles of Na2S in 1 liter of solution

So there are 0.526 moles of Na2S in x liter of solution.

X liter of solution = 0.526 mol of Na2S x 1 liter of solution / 225 mol of Na2S = 0.0023 liters, that is, 2.3 ml

Therefore, 0.0023 liters of 225M Na2S solution is required.

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An alpha particle bombardment of aluminum with an atomic number of 27 results in the production of a neutron and phosphorus 15. The particular isotope formed is aluminum-28.

Fundamental alterations take place at the level of the atomic nucleus during nuclear reactions. Analyze the properties of the neutron, which has a mass similar to that of a proton but no electric charge. As a result, when it interacts with the aluminum core, the atomic number should remain constant but the atomic mass should rise by one unit. The newly produced atom is in an excited state when it transitions to the base state with the emission of a high-energy radiation called a gamma ray. Aluminum-28 isotope is formed.   ⁷A₂₇ + ⁰n₁ → ⁷Al₂₈ˣ

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After 4 minutes, 400 g of the sample would have decayed to 400 g -  (200 g x 4) = 396.2 g.

Protactinium (symbol Pa) is a rare, radioactive, metallic element in the actinide series of the periodic table. It has an atomic number of 91 and an atomic mass of 231. It is found in trace amounts in nature, but can be artificially produced in a nuclear reactor. Protactinium is a soft, silvery-gray metal that is soluble in acids and insoluble in bases. It has a high melting point and is moderately toxic. It has a variety of uses, including as a fuel source in nuclear reactors and in medical research.

After 4 minutes, 400 g of protactinium-234 would have decayed to approximately 396.2 g.
This is because the half-life of protactinium-234 is 1 minute, meaning that in one minute, half of the original amount (200 g) of the sample will decay.

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0.5 moles are present in 20 grams of calcium.

The mole, which is denoted by the symbol "mol," is the volume of a system that includes as many elementary particles as there are atoms in 0.012 kilograms of carbon 12.

The number of atoms, molecules, or ions that make up one mole of a substance is 6.022 × 10²³ . The term "Avogadro's number" or "Avogadro's constant" refers to the number 6.022 × 10²³

Atomic Mass of Calcium = 40u

(Atomic Mass is same as Molar Mass, so)

Molar Mass of Calcium = 40g

Formula to find number of moles

Number of Moles = given mass / molar mass

                                = 20 / 40   = 0.5 moles

Therefore, 0.5 moles are present in 20 grams of calcium.

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The complete question is

How many moles are there in 20 g of calcium

Answer:

im here for the points

Explanation:

HAHA

Answer:

64.5g

Explanation:

First you add the mass of reactant 1 and reactant 2, then you simply subtract the amount of gas released from your answer, and that would be the total mass of ALL the products formed.

My work:

13.6g + 72.9 = 86.5g

86.5g - 22g = 64.5g

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore,  the volume of oxygen needed to completely react with 171.9 g of S8 at STP is 180.09L.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

S[tex]_8[/tex](s) +12O[tex]_2[/tex](g) →8SO[tex]_3[/tex](l)

171.9 g of S8

mole of  S[tex]_8[/tex]=  171.9 g/ 256.52g/mol

                 =0.67mol

The mole of oxygen = 12×0.67

                                = 8.04mol

volume of oxygen= 22.4× 8.04

                            =180.09L

Therefore,  the volume of oxygen needed to completely react with 171.9 g of S8 at STP is 180.09L.

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It is critical to develop a PheDH with specificity and high activity since it is crucial for the manufacture of chiral pharmacological intermediates and the detection of phenylketonuria.

Here, a PheDH gene, pdh, was discovered that encodes a novel BhPheDH with 61.0% similarity to the previously identified PheDH from Microbacterium sp. In comparison to the PheDH from Nocardia sp., the BhPheDH demonstrated superior stability in hot environments (40–70°C) and optimal activity at 60°C and pH 7.0. Additionally, sodium salt has the potential to greatly boost both its activity and thermostability. The residual activity of the BhPheDH was found to be 1.8-fold higher than that of the control group following incubation for 2 hours in 3 M NaCl at 60 °C (without NaCl).

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Answer:

c. The circulatory system moves oxygen throughout the body that is brought in by the respiratory system.

Explanation:

The circulatory system delivers oxygen and nutrients to cells and takes away wastes.

The respiratory system is the network of organs and tissues that help you breathe.

So, of the options, option c is correct.

Hope this helps!

The  statement which  best describes how two body systems work together to maintain homeostasis is that circulatory system moves oxygen throughout the body that is brought in by the respiratory system.

In biology, homeostasis  is the state of steady internal, physical, and chemical conditions maintained by living systems.This is the condition of optimal functioning for the organism and includes many variables, such as body temperature and fluid balance, being kept within certain pre-set limits (homeostatic range).

Other variables include the pH of extracellular fluid, the concentrations of sodium, potassium, and calcium ions, as well as the blood sugar level, and these need to be regulated despite changes in the environment, diet, or level of activity. Each of these variables is controlled by one or more regulators or homeostatic mechanisms, which together maintain life.

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Answer:

Decrease temperature with increase in ammonium nitrate concentration.

Explanation:

The temperature changes when different masses of ammonium nitrate are dissolved in water because the ammonium nitrate takes energy from the surrounding water environment for the breaking of ionic bonds as a result the temperature of water decreases. When more concentration of ammonium nitrate is added to water, more decrease occur in temperature of water and the water becomes cold.

The empirical formula of this compound is Ca3(PO4)2.

What is an Empirical formula?

An empirical formula is a type of chemical formula that shows the simplest ratio of atoms in a molecule, rather than the total number of atoms. It is the simplest possible chemical formula that shows the relative numbers of each type of atom in a molecule.

The molecular formula is Ca3(PO4)2•H2O, which indicates that the compound is composed of three calcium atoms, two phosphate atoms, and two water molecules. The molar mass of this compound is 1004 g/mol, which is two times the molar mass of the empirical formula (502 g/mol). Therefore, the molecular formula of this compound is Ca3(PO4)2•H2O.

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The relative acidity of orange juice compared to pure water is 1000times. The relationship between acid strength and pH is inverse.

A scale that historically denoted "potential of hydrogen" was used to describe how basic or acidic an aqueous solution was. The pH values of acidic solutions are typically lower than those of basic or alkaline solutions. The pH scale can be used to gauge how strong an acid is. Higher pH values result in weaker acids, while lower pH values result in stronger acids. Therefore, we may conclude that the relationship between acid strength and pH is inverse.

Given the pH of orange juice = 4

Then concentration of orange juice (M1) = 10^-4M

pH of pure water = 7

The concentration of [H+] in water (M2) = 10^-7M

The relative pH = 10^-4/10^-7 = 10^3

Hence  its relative acidity compared to pure water is 1000 times.

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Answer:

1.5 grams of carbon dioxide

Explanation:

According to this question, a dash of vinegar and baking soda balloon system weighed 65 grams. The system weighted 63.5grams after releasing the carbon dioxide in it.

This means that, to get the amount of carbon dioxide (CO2) produced in the system, we subtract the mass of the system after releasing CO2 from the initial mass of the system before releasing CO2.

That is;

Mass of CO2 produced = 65g - 63.5g

Mass of CO2 produced = 1.5grams

For a team of scientists to claim that they have discovered a new experimental method for determining atomic mass, their claim is to be considered valid only if another team of scientists is able to replicate the results of the experiment.

In order for a scientific claim to be considered valid, it is important that the results of the experiment can be replicated by other researchers.

Replication means that other scientists should be able to obtain the same results using the same methods. This helps to ensure that the results are accurate and reliable, rather than being a fluke or an error.

Without the ability to replicate the results, it is difficult to have confidence in the validity of the claim, as it may be due to uncontrolled variables or other factors that cannot be reproduced. Ensuring that results are replicable is an important part of the scientific process and helps to build a strong foundation of knowledge.

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Answer:

[tex]\huge\mathfrak\purple{answer..} \\ \\ \huge\mathfrak\green{atomic \: number} \\ \\ \huge\mathfrak\red{hope \: it \: helps...}[/tex]

The final pressure is 6312.935 Pa.

The final pressure of the gas can be calculated using the Ideal Gas Law, PV = nRT.

In this situation, the volume of the gas is doubled and the temperature is increased from 30 degrees Celsius to 80 degrees Celsius, while the number of moles of gas and the ideal gas constant remains constant.

Therefore, the pressure of the gas will decrease as the volume doubles and the temperature increases. The final pressure can be calculated by multiplying the initial pressure by the ratio of the initial volume to the final volume and the ratio of the final temperature to the initial temperature.

Final pressure = (Initial pressure) x (Initial volume / Final volume) x (Final temperature / Initial temperature)

The initial pressure is 67cm mercury. 1cm mercury = 133.322 Pa so 67cm mercury = 67*133.322 =8933.294 Pa.

The final temperature is 80-degree celsius = 80+273 = 353K

The final pressure =8933.294 x (1/2) x (353/303) = 6312.935 Pa

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Answer:

true hope it helps

Explanation:

have a nice day

Chemistry quizzes What is the mass  of a single carbon atom if a mole of carbon atoms weighs 12 grams. The fact that 1 mole of carbon atoms weighs 12 grams is a given.

There are 6. 022 10 23 atoms in total, or Avogadro's number, in a mole of carbon atoms. As a result, 1 carbon atom weighs 2 10 - 23 g (in grams). The weight of one mole of carbon atoms is 12 g. 12 g to 12 amu. Because we defined the mole to make it so, the atomic mass and molar mass are in agreement. A material can have a variable mass per mole while yet having the same number of particles. Are there any examples you might use to support the claim? In current usage, the term "mole" merely denotes a group of countable items, more specifically the Avogadro number of the entities in question.

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Answer:

Explanation: 8.43

In literary classes, the three most popular types are verbal irony, dramatic irony, and situational irony. When a speaker or narrator says something that contradicts what they mean, what they intend, or what the context necessitates, this is called verbal irony.

One thing is expressed while another is meant in an ironic statement. For example, on a chilly, wet gray day, you would exclaim, "What a gorgeous day!" Alternatively, if you were suffering from a severe case of food sickness, you may respond, "Wow, I feel terrific today." "ffers points of view and ideas that are, at most, intriguing... However, it does not reach the truth." Ronagh and Souder are particularly concerned with scientific assertions that are not meant to be taken seriously.

Here,

The three most common varieties in literary studies are verbal irony, dramatic irony, and situational irony. Verbal irony occurs when a speaker or narrator says something that contradicts what they mean, what they intend, or what the context requires.

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Answer:

Why do animals and plants have different habitats?

This is because the planet has different climates and different environments in every continents, organisms have evolved and adapted to these factors, that is why they have different habitats as well.

It is safe to say that organisms and their environment really are interrelated and needs each other in order to survive and continue.

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Answer:

Explanation:

Although stochiometry is very scary loking math it is very easy and and fun to learn.

First Balance the chemical equation (Meaning there are equal amounts of elements at end and begining

Second Convert your units to mols

mols are what allows for stochiometry math to work to know how to find the mols takes practice and knowing when to write the math.

Then from there is just knowing how to go from grams to kg or g to mg and etc

Answer:  The total pressure of the container is 231.97 kPa.

Explanation:

Given: [tex]P_{H_{2}} = 85.42 kPa[/tex],        [tex]P_{O_{2}} = 3.2 kpa[/tex]

[tex]P_{F_{2}} = 22.65 kPa[/tex],            [tex]P_{Cl_{2}} = 65.3 kPa[/tex]

Total pressure is the sum of pressure of each component of the gas present in a vessel or container.

Hence, total pressure of the container is calculated as follows.

[tex]P_{total} = P_{H_{2}} + P_{O_{2}} + P_{F_{2}} + P_{Cl_{2}} + P_{N_{2}}\\= 85.42 kPa + 3.2 kPa + 22.65 kPa + 55.4 kPa + 65.3 kPa\\= 231.97 kPa[/tex]

Thus, we can conclude that the total pressure of the container is 231.97 kPa.

Answer:

Carbon moves from the atmosphere to the land, ocean, and life through biological, chemical, geological and physical processes in a cycle called the carbon cycle. Because some carbon gases are greenhouse gases, changes in the carbon cycle that put more carbon in the atmosphere also warm Earth’s climate.