1. The heat of combustion is a negative value. Do you think this indicates an exothermic or endothermic reaction? Explain.​

Answers

Answer 1

Answer:

Exothermic

Explanation:

Combustion reactions are almost always exothermic because it is an oxidation reaction that produces heat and in this case it would be considered to be exothermic but there are few cases in which it would be considered endothermic. Combustion of Nitrogen is endothermic because Δ  is positive despite being a combustion reaction.


Related Questions

what will you observe when you open a bottle of concentrated hydrochloric acid?

Answers

Answer:

Strong affinity of HCl gas for moisture in air results in forming of droplets of liquid solution which appears like a cloudy smoke.

Explanation:

#followformore

Hope this helps :)

Describe the process of pasteurization?

Answers

Answer:

Pasteurization is a process in which packaged and non-packaged foods (such as milk and fruit juice) are treated with mild heat, usually to less than 100 °C (212 °F), to eliminate pathogens and extend shelf life.

I need HELP A.S.P
B. A +ion (positive ion, one with extra positive charge)?

Answers

Answer:
If an ion has a positive charge then it has lost an
electrons.
Explanation:
So you don't "gain" anything when the ion has a
positive charge. It loses an electron which
means it has more protons than electrons. Thus,
the ion has a positive charge. If it "gained" an
electron then it would have a negative charge.

I need help with the question below

Answers

Answer:

the answer is Crystal structures

Beryllium (Be) has four electrons. Fluorine (F) has nine electrons. Which chemical formula shows the correct subscripts for the product of the reaction when beryllium and fluorine combine

Answers

Answer:

BeF2

Explanation:

The correct chemical formula for the product of the reaction when beryllium and fluorine combine is BF₂.

The valence electron of an atom determines how an atom goes into bonding.

Beryllium(Be) has 4 electron and has 2 valence electron. To fulfil the octet rule, it can easily give out this 2 electron during bonding.

Fluorine(F) has 9 electrons and 7 valency electrons. To fulfil the octet rule, it readily accepts a single electron.

The correct chemical formula for the product of the reaction when beryllium and fluorine combine is BF₂.

This means 1 atom of beryllium combines with 2 atoms of fluorine to form beryllium fluoride. The beryllium give its 2 valency electrons to the 2 atoms of fluorine. The 2 atoms of fluorine will now have a valency electron of 8 each. The octet rule has been fulfilled at this point.

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Answers

thank you for the points

A gas measures 140 mL at 400 K find its volume at 120 K if the pressure remains constant.

Answers

By applying Charles law, the final volume of the gas is equal to 42 mL.

Given the following data:

Initial volume = 140 mLInitial temperature = 400 KFinal temperature = 120 K

To find the final volume of the gas, we would apply Charles law:

Charles law states that when the pressure of an ideal gas is kept constant, the volume of the gas is indirectly proportional to the absolute temperature of the gas.

Mathematically, Charles law is given by the formula;

[tex]\frac{V}{T} =k\\\\\frac{V_1}{T_1} = \frac{V_2}{T_2}[/tex]

Where;

T is the temperature of an ideal gas.V is the volume of an ideal gas.

Substituting the given parameters into the formula, we have;

[tex]\frac{140}{400} = \frac{V_2}{120} \\\\140 \times 120 = 400V_2\\\\16800 = 400V_2\\\\V_2 = \frac{16800}{400}[/tex]

Final volume = 42 mL.

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A tiny crystal of a solid substance is added to an aqueous solution of the same substance. What would happen if the original solution was: 1) Super saturated 2) Unsaturated 3) Saturated.

Answers

Answer:

3.)Saturated

Explanation:

it was saturated and then turned super saturated

When potassium metal is placed in water, a large amount of energy is released as potassium hydroxide and hydrogen gas are produced in the reaction 2K(s) + 2H2O(l) → 2KOH(aq) + H2(g). Your lab partner says this is a redox reaction and a combustion reaction. Do you agree? Defend your answer by explaining whether or not it meets the requirements of each type of reaction.

Answers

This is a redox reaction but not a combustion reaction.

Redox Reaction

A type of chemical reaction that involves a transfer of electrons or gain of electrons between two-element. An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes.

Combustion reaction

It must have two products. CO2 and H2Ooxygen in the reactant is must.

∴ The reaction is Redox ✓ not combustion

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what causes chemical change in the stomach?

Answers

Answer:

The chemical change in the stomach, known as food digestion,  is from the enzymes in the liver and stomach where they break down food molecules into even smaller molecules in order for them to be digested more easily.

9. The “power plant” of the cell is the

(a) nucleus.

(b) ribosome.

(c) chloroplast.

(d) mitochondria.

Answers

Answer:

D. Mitochondria

Explanation:

The mitochondria, labeled the powerhouse of the cell, are the organelle responsible for energy production within the cell

(D) the mitochondria provide energy through the cell through aerobic respiration :)

Which animal resembles their parents already after being born or hatched?

Answers

i think maybe reptiles bu i could be wrong. :)

how many different types of nucleotides are found in nucleic acids

Answers

Answer: four different types!!!!

Explanation:

Something that potatoes and bacteria have in common is that they both reproduce(1 point)


via vegetative reproduction.

using tubers.

via binary fission.

asexually.

Answers

Asexually

Potatoes reproduce asexually through the vegetive propagation mechanism. They have microscopic eyeballs which produce scaly leaves, and new potato plants emerge from these leaves. Only a single individual is responsible for the development of a new species.

Bacteria(Prokaryotes) reproduce asexually through binary fission, where the parent organism divides itself into two, producing genetically identical clones of itself.

The things that potatoes and bacteria have in common is that they both reproduce asexually. Thus option 4 is correct.

What is reproduction?

Reproduction is defined as the biological process that creates new individual organisms from existing ones, also referred to as "offspring"

It can also be defined as the process by which identically minded organisms make new organisms.

There are two types of reproduction.

Sexual reproduction - It is defined as a method of reproduction whereby male and female gametes combine to create an offspring.Asexual reproduction - It is defined as a method of reproduction that doesn't modify the number of chromosomes or involve the fusing of gametes.

Thus. the things that potatoes and bacteria have in common is that they both reproduce asexually. Thus option 4 is correct.

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please help as soon as possible!!!

Answers

Answer:

the kidney control the amount of water, ion, and other substances in the blood by excreting more or less of them in urine, also secretes the hormones that help maintain homeostasis

What must desert plants do to survive?
Ostore rainwater
Ogrow very tall
have big leaves

Answers

Store rainwater, like a Cactus

According to Dalton, atoms cannot be SELECT ALL THAT APPLY a Created b Destroyed c Subdivided d Bonded​

Answers

Answer:

The answer is subdivided,created or destroyed

Who was the first person to introduce the concept of atomic mass?

Answers

John dalton is the answer

What is collision theory?

A.a theory stating that reactants must collide with products in order for a chemical reaction to occur

B.a theory stating that there must be minimal kinetic energy between products for a chemical reaction to occur

C.a theory stating that a chemical reaction occurs only when reactants strike each other at the correct orientation and with sufficient kinetic energy

D.a theory stating that a chemical reaction occurs only when reactants are placed in separate containers and the containers are then placed close together

Answers

Answer:

A

Explanation:

collision theory is a theory used to predict the rates of chemical reactions, particularly for gases. The collision theory is based on the assumption that for a reaction to occur it is necessary for the reacting species (atoms or molecules) to come together or collide with one another

the temperature of absolute zero is stated as ___________.

Answers

Answer:

-273.15 degrees Celsius

-459.67 degrees Fahrenheit

It is considered to be coldest conceivable temperature and is impossible to reach

Explanation:

If you are looking for degrees it is

-273.15 degrees Celsius

-459.67 degrees Fahrenheit

or just 0 on the keilvin scale

cyclic voltametry allows one to measure the __________ of a compound.

Answers

Answer:

*two parameters

Explanation:

¿Cuál es la partícula mas pequeña del átomo?

Answers

Answer:

Los quarks son ciertamente unas de las partículas más pequeñas del universo. Son elementales, indivisibles y no se pueden romper en piezas menores.

Explanation:

what scientist is credited with formulating the octet rule

Answers

Answer:

The electron configuration of the neon atom. American chemist Gilbert Lewis (1875-1946) used this observation to explain the types of ions and molecules that are formed by other elements. He called his explanation the octet rule.

Propose an explanation for why the element carbon, rather than sodium, is important in forming natural polymers?
I need this ASAP

Answers

Carbon has a one-of-a-kind ability to make covalent bonds with a wide range of other atoms. It has the ability to form bonds with other carbon atoms as well as atoms from other elements. Carbon frequently forms polymers as a result of this capacity. A polymer is a big molecule composed of numerous smaller molecules linked together by covalent bonds.

EASY QUESTION (PLEASE HELP THE INTERNET ISN'T SUCH A BIG HELP RIGHT NOW)
Things microscopes have helped scientists discover about cells.
(No links plz)

Answers

Microscopes allowed scientists to study Bacteria and Archaea, which are prokaryotic cells. These are tiny cells with no membrane-bound organelles. It allowed them to study Eukaryotic cells with a nucleus and membrane-bound organelles that perform various activities throughout life.

Answer:

Adding on to the answer said before, microscopes are pretty much one of the most significant tools used in Biology. It helped discover organelles, and smaller stuff like DNA, and prominently allowed Scientists to discover Bacteria and Archaea, the prokaryotic cells that contribute a big role in the functioning of soil, which is essential for our ecosystem.

Blood has a mass-volume percent of NaCl of 0.9%. What mass (g) of NaCl is present in a liter of blood

Answers

The mass (g) of NaCl that is present in a liter of blood is 0.347g.

HOW TO CALCULATE MASS:

The mass of a substance can be calculated by multiplying the decimal mass-volume of the substance by its molar mass.

According to this question, Blood has a mass-volume percent of NaCl of 0.9%. This means that 0.9/100 = 0.009g of NaCl is present in each 100g of blood.

Molar mass of NaCl = 23 + 35.5 = 38.5g/mol

Mass of NaCl in a liter of blood = 38.5 × 0.009

Mass of NaCl in a liter of blood = 0.347g of NaCl.

Therefore, The mass (g) of NaCl that is present in a liter of blood is 0.347g.

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According to Dalton, atoms of different elements will be____________.

Answers

Answer:

The atoms of different elements vary in size and mass.

Explanation:

C. A - ion (negative ion, one with extra negative charge)?

Answers

Answer:

Negative ion with one extra electron.

BRAINLIST Pls

Anions are the name for ions that have a negative charge. The body contains several common chemicals as ions. Sodium, potassium, calcium, chloride, and bicarbonate are typical examples.

What are anions ?

Negatively charged electrons are called anion. When non-metals gain electrons, they are produced. They absorb one or more electrons. They have a negative charge overall as a result. The ion concentration iodide ( I- ), chloride ( Cl- ), and hydroxide are among examples ( OH– ).

The electrode where reduction takes place in any electrochemical cell  is characterized as the cathode. On the other extreme, the positive electrode will draw anions, or negative ions, to itself.

Thus, when an atom obtains electrons, it transforms into the negatively-charged ion known as an anion.

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What is the periodic table? ​

Answers

here u go hope it helps

Answer:

The periodic table, also known as the periodic table of chemical elements, is a tabular display of the chemical elements. It is widely used in chemistry, physics, and other sciences, and is generally seen as an icon of chemistry.

Explanation:

The periodic table is a tabular arrangement of chemical elements that classifies elements according to repeating qualities and is structured by increasing atomic number. Metals are located on the left side of the table, whereas nonmetals are located on the right. The columns are referred to as groupings.

in pic

____________________________________________________

(Hope this helps can I pls have brainlist (crown)

When carbon dioxide enters the blood, some of it combines with ____________ to form carbaminohemoglobin, but most of it becomes ____________ ions that diffuse into the blood plasma.

Answers

Answer:

hemoglobin to become bicarbonate

Explanation:

When carbon dioxide enters the blood it combines with hemoglobin to form carbamino hemoglobin or carboxyhemoglobin but most of it becomes carbonate ions and diffuse into the blood plasma.

What is carboxyhemoglobin?

Hemoglobin is a blood protein giving red colour to the blood. It helps to transport oxygen everywhere. When oxygen fills in the air sack, it combines with oxygen and form oxyhemoglobin.

However, hemoglobin have more affinity towards carbon dioxide and and they combines to form carbaminohemoglobin which prevents the transportation of oxygen through blood.

The carbon dioxide will be converted into carbonic acid by combining with water. This acid then forms its carbonate ions and these ions helps to maintain the blood pH to be constant.The carbonate ions, CO₃²⁻can easily diffuse into blood plasma.

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