Which of the following is the best thermal insulator to reduce the transfer of
heat by convection?
A. Air
B. Water
C. Alcohol
D. A vacuum

B. A circle.

The center void shape that generates the most thrust in a solid fuel rocket is a circle.

What is Fuel?

Fuel is a substance that is used to produce heat or energy through combustion or other chemical reactions. It can be in the form of a solid, liquid, or gas and is typically used to power engines, generators, or heating systems. Examples of fuels include gasoline, diesel, natural gas, coal, wood, and propane. The choice of fuel depends on factors such as availability, cost, energy content, and environmental impact.

This is because a circular shape allows for the most efficient burning of the fuel, with the flame front moving evenly in all directions. Other shapes, such as a heart, triangle, or tree with branches, can cause uneven burning and may result in less thrust.

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Answer:

Explanation:

D.
tree with branches

Answer:

measurements are important to do calculations to get correct results and without them scientists cannot form theories

Answer:

electron configuration

Explanation:

The arrangement of electrons in the atomic orbitals of an atom is called the electron configuration. Electron configurations can be determined using a periodic table.

Answer:

B. An alkyne

Explanation:

Octynes are alkynes with one triple bond

Answer:

Scientific Method

Explanation:

Science is empirical in nature. The entire purpose of science is to discover new knowledge.

The empirical research method in science all begins with gathering observations from phenomena. After that, the researcher formulates appropriate hypothesis which are rigorously tested.

The conclusions drawn from testing the original hypothesis validate or modify the original hypothesis.

Answer:

Cr ^ 3 +

Explanation:

Recordemos que el número atómico es el número de protones en el núcleo del átomo. También corresponde al número de electrones en el átomo neutro.

Dado que el número de protones es 24, entonces el elemento debe ser cromo.

Si hay 21 electrones presentes, entonces se deben haber perdido 3 electrones para dar Cr ^ 3 +.

Answer:

the answer is option E they are bronsted lowry acid

Answer:

See explanation

Explanation:

An electrolytic cell functions by a non spontaneous chemical process. Energy is supplied in the form of electricity through a battery to drive the electrochemical process.

A voltaic cell functions by a spontaneous chemical process. Energy or work can be derived from a voltaic cell.

When iron is rusting, a natural voltaic cell is set and the iron is converted to hydrated iron III hydroxide. The set up used for the extraction of sodium metal from brine functions on the basis of electrolysis.

Answer:

A. The red side is acidic.

B. Because it has more positive hydrogen ions.

C. The blue side is basic.

D. Because it has more negative hydroxide ion.

Given the data from the question,

A. The side with more H⁺ is acidic

B. It is acidic because it contains more H⁺

C. The side with more OH¯ is basic

B. It is basic because it contains more OH¯

This is simply a measure of the acidity / alkalinity of a solution.

The pH measures the hydrogen ion concentration while the pOH measures the hydroxide ion concentration

The pH scale is a scale that gives an understanding of the variation of the acidity / alkalinity of a solution.

The scale ranges from 0 to 14 indicating:

The presence of H⁺ indicates acidity.

Thus, the side with more H⁺ is acidic.

The presence of OH¯ indicates the solution is basic.

Therefore, the side with more OH¯ is basic

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Answer:

isotope 2

Explanation:

it has the highest percentage abundance

Answer:

Physical chemistry is the study of macroscopic, and particulate phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mechanics, analytical dynamics and chemical equilibrium while environmental chemistry is the study of chemical processes that occur in water, air, terrestrial and living environments, and the effects of human activity on them. 

Physical chemistry is the area of chemistry that deals with how materials interact and change. The scientific study of chemical and biological phenomena that take place in the environment is known as environmental chemistry.

Physical chemistry attempts to quantify, correlate, and explain the quantitative features of reactions by focusing, in contrast to other branches, on the physics principles that underlie all chemical interactions (such as the gas laws).

While environmental chemistry is the study of chemical species' sources, reactions, movement, impacts, and fates in the air, soil, and water environments, as well as the impact of human activity and biological activity on these, can be summed up as the field of chemical ecology.

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Answer:  b) a chemical reaction between carbohydrates and oxygen to produce carbon dioxide, water, and heat energy

Explanation:

Based on the options, I assume that this is talking about the process of respiration. Respiration allows living things to produce energy by reacting carbohydrates with oxygen.

This results in the release of energy in the form of heat in a cell and also the formation of carbon dioxide and water. This type of respiration is known as Aerobic respiration.

Metal containers are not used for storing acid because most of the time acid reacts with almost every metal and produces salts or oxides which alters the acid characteristics making it useless....

Explanation:

i) Melting point = 15°C and Boiling point = 110°C

ii) The region C on graph there is only liquid state, the region A on graph there is only solid state.

iii) The straight line A1 - B1 shows that the melting point of solid wax and getting converted to liquid form.

iv) Latent heat of vaporization is a physical property of a substance.

It is defined as the heat required to change one mole of liquid at its boiling point under standard atmospheric pressure. 

v) At 'B' the wax is at both solid and liquid state

Answer:

3.1 kg

Explanation:

Step 1: Write the balanced combustion equation

C₈H₁₈ + 12.5 O₂ ⇒ 8 CO₂ + 9 H₂O

Step 2: Calculate the moles corresponding to 1.0 kg of C₈H₁₈.

The molar mass of C₈H₁₈ is 114.23 g/mol.

1.0 × 10³ g × 1 mol/114.23 g = 8.8 mol

Step 3: Calculate the moles of CO₂ produced from 8.8 moles of C₈H₁₈

The molar ratio of C₈H₁₈ to CO₂ is 1:8. The moles of CO₂ produced are 8/1 × 8.8 mol = 70 mol.

Step 4: Calculate the mass corresponding to 70 moles of CO₂

The molar mass of CO₂ is 44.01 g/mol.

70 mol × 44.01 g/mol = 3.1 × 10³ g = 3.1 kg

Answer:

cfvgbhnjmk,

Explanation:

Answer:

a. po tamang sagot

Explanation:

pa pafoolow po pleasr

The DNA and RNA are polynucleotides which contain a chain of nucleotides monomers with different nitrogenous bases. Each  nucleotide different from the others, as  It has different bases. The correct option is A.

A nucleotide is defined as a compound containing three component units, namely a pentose sugar (either ribose or 2-deoxyribose), a heterocyclic nitrogenous base (a substituted purine or a substituted pyrimidine) and a phosphate group.

The nucleotides are the phosphate esters of nucleosides. A nucleotide containing ribose as the sugar unit is termed as the ribonucleotide. While one containing 2-deoxyribose as the sugar unit is termed as the deoxyribonucleotide.

The nitrogenous bases in RNA are adenine, guanine, cytosine and uracil whereas in DNA the bases are adenine, guanine, cytosine and thymine. The purines are adenine and guanine whereas cytosine, thymine and uracil are pyrimidines.

Thus the correct option is A.

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Answer:

See explanation

Explanation:

For a chemical system in a state of dynamic equilibrium, the rate of forward reaction is equal to the rate of reverse reaction.

For this system under consideration;

I2(s)⇄I2(g)

When we heat the container, solid iodine is converted into purple coloured iodine vapour.

When equilibrium is achieved in the system, there will be no net change in the amount of solid iodine and iodine vapour present in the system since the rate of forward and reverse reactions are equal for a system in a state of equilibrium.

Answer:

P2 = 900 mmHg.

Explanation:

Given the following data;

Initial pressure = 450 mmHg

Initial temperature = 100°C

Final temperature = 200°C

To find the final pressure, we would use Gay Lussac's law;

Gay Lussac states that when the volume of an ideal gas is kept constant, the pressure of the gas is directly proportional to the absolute temperature of the gas.

Mathematically, Gay Lussac's law is given by;

[tex] PT = K[/tex]

[tex] \frac{P1}{T1} = \frac{P2}{T2}[/tex]

Making P2 as the subject formula, we have;

[tex] P_{2}= \frac{P1}{T1} * T_{2}[/tex]

[tex] P_{2}= \frac{450}{100} * 200 [/tex]

[tex] P_{2}= 4.5 * 200 [/tex]

Final pressure, P2 = 900 mmHg.

Answer:

If 1000. mL of water freezes, which of the following is a reasonable approximation for the volume of the resulting ice?

Group of answer choices

1000. mL

961 mL

1040 mL

Explanation:

Ice is fewer denser than water.

The reason is the volume occupied by the same mass of ice with water is more than the volume occupied by water. Ice has more empty space within it.

Due to this reason, ice floats on water.

When 1000ml of water freezes to ice then its volume is greater than water.

Among the given options the correct answer is 1040 mL .

Answer:

There is 9.6 grams of CO2 produced

Explanation:

Step 1: Data given

Mass of methane = 5.50 grams

Molar mass of methane = 16.04 g/mol

Mass of oxygen = 13.9 grams

Molar mass of oxygen = 32.0 g/mol

Step 2: The reaction

CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)

Step 3: Calculate number of moles

Moles = mass / molar mass

Moles methane = 5.50 grams / 16.04 g/mol

Moles methane = 0.343 moles

Moles oxygen = 13.9 grams / 32.0 g/mol

Moles oxygen = 0.434 moles

For 1 mol CH4 we need 2 moles O2 to produce 1 mol CO2 and 2 moles H2O

O2 is the limiting reactant. It will completely react (0.434 moles).

There will react 0.434/2 = 0.217 moles CH4

There will remain 0.343-0.217 = 0.126 moles CH4

There will be produced 0.434 moles of H2O and

0.434/2 =0.217 moles of CO2

Step 4: Calculate mass of products

Mass = moles * molar mass

Mass CO2 = 0.217 moles ¨44.01 g/mol

Mass CO2 = 9.6 grams

Mass H2O = 0.434 moles * 18.02

Mass H2O = 7.8 grams

Answer:

9.5 hours/ 9 hours 30 mins

Explanation:

Distance = speed × time so

Time = Distance ÷ speed

= 570 ÷ 60

= 9.5 hours

Answer:

VSEPR theory

Explanation:

The valence shell electron pair repulsion theory was propounded by Gillespie and Nylom (1957).

The entire idea of the VSEPR theory is that the shape of a molecule depends on the electrostatic repulsion between electron pairs surrounding the central atom in a molecule which causes these pairs to be separated as far as possible.

The shapes of many molecules can be accurately predicted based on this model.

Answer:

a process that involves rearrangement of the molecular or ionic structure of a substance, as distinct from a change in physical form or a nuclear reaction.

Or

Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products. ... A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.

Answer:

1.2 × 10³ L

Explanation:

Step 1: Calculate the total number of gaseous moles

n = nH₂ + nCl₂ = 100 mol + 100 mol = 200 mol

Step 2: Convert 30 °C to Kelvin

We will use the following expression.

K = °C + 273.15 = 30 + 273.15 = 303 K

Step 3: Calculate the volume of the container

We will use the ideal gas equation.

P × V = n × R × T

V = n × R × T / P

V = 200 mol × (0.0821 atm.L/mol.K) × 303 K / 4 atm = 1.2 × 10³ L

Answer:

Boiling, melting

Explanation:

Physical changes affect the form of a chemical substance.

Answer:

Ca(OH)2 is base

is answer of this question

hope this will help you more

Answer:

Ca(OH)2

Explanation:

Got it right on the test

Answer: For the given reaction-

Explanation:

For example, Tin + silver nitrate = tin (IV) nitrate + silver

The 'equal to' symbol denotes a forward arrow.

For example, [tex]Sn + AgNO_{3} \rightarrow N_{4}O_{12}Sn + Ag[/tex]

 [tex]Sn(s) + 4AgNO_{3}(aq) \rightarrow N_{4}O_{12}Sn(aq) + 4Ag(s)[/tex]