when it is time to end a reflux, first choose... and then turn off the heat. choose... until the system has cooled.

Answers

Answer 1

Answer:

second one is better

Explanation:

system is very much hot in first state..so wait for cooling down the system..but these depend on the organic compounds and products you are using. sometimes we need to carryout further steps in hot state..then you can't wail it to cool down


Related Questions

differentiate between atomic mass and atomic number​

Answers

Answer:

The major difference between atomic number and mass number is that the atomic number states the number of protons present in an atom whereas, the mass number indicates the total of the number of protons and the number neutrons present in an atom.

Explanation:

The nucleus of most atoms is composed of which of the following sub-atomic particles?

A. tightly packed protons.
B. tightly packed neutrons.
C. tightly packed protons and neutrons.
D. loosely connected protons and electrons.

Answers

Answer:

C. Tightly packed protons and neutrons

Explanation:

It consists of two sub-atomic particle namely proton and neutron.

This dense nucleus is responsible for most of the mass of atom.

Answer:

C. tightly packed protons and neutrons

Explanation:

The nucleus of an atom is made of protons and neutrons with electrons orbiting the nucleus.

Three fundamental laws of chemical combination

Answers

Answer:

the law of multiple proportions, law of definite proportions, and law of conservation of mass.

Explanation:

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

pls help ASSSAPPPP!!!!

Answers

Answer:

b or d

Explanation:

Answer:

The answer is B (it's reactivity)

In terms of attractive forces, explain why LiClhas a higher melting point than SCI2.​

Answers

Answer:

Well, SCl2 is known, so is disulfur dichloride… Cl−S−S−Cl …and BOTH these species are molecular… On the other hand, lithium chloride, an ionic salt, is decidedly non-molecular, and consists of an infinite array of lithium and chloride ions held together by strong electrostatic forces ….. and thus we would expect the salt to have the much higher melting point….

Which of the following statements is correct regarding the speed and velocity of an object? A. An object’s speed is determined by the distance the object traveled and how long it took the object to travel that distance. B. An object’s velocity is determined by the distance the object traveled, how long it took the object to travel that distance and what acceleration the object traveled. C. An object’s velocity is determined by the distance the object traveled and how long it took the object to travel that distance. D. An object’s speed is determined by the distance the object traveled, how long it took the object to travel that distance and what direction the object traveled.

Answers

Answer:

Explanation:

D

An object’s speed is determined by the distance the object traveled, how long it took the object to travel that distance, and what direction the object traveled. This statement is correct regarding the speed and velocity of an object.

What is velocity ?

The directional speed of an item in motion, as measured by a specific unit of time and viewed from a certain point of reference, is what is referred to as velocity.

Velocity is the pace and direction of an item's movement, whereas speed is the time rate at which an object is travelling along a route.

Constant acceleration and constant velocity are both forms of motion, as you have already read. Because acceleration is the rate at which velocity changes, constant velocity and constant acceleration go hand in hand.

Thus, option D is correct.

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204,900,000,000
How many significant digits are found?

Answers

Answer:

4

Explanation:

There are 4 significant figures because when there is not a decimal, then only numerical values over 0 are counted. So the numbers counted in sig figs are 2049, and none of the other 0s.

So if it was 204,900,000,000.0, then it would have 12 significant figures.

What is it called when a substance is in-between two states of matter?

Answers

Answer:

There are four natural states of matter: Solids, liquids, gases and plasma. The fifth state is the man-made Bose-Einstein condensates. Solids.

Explanation:

Hope this helps you out!!

What type of intermolecular bond may form between na and br

Answers

Answer:

Ionic

Explanation:

Na is a metal and Br is a non-metal. Makes an ionic bond. Hope that helps

What is the. chemical formular name of rusting?

Answers

Answer:

Iron(III) oxide

Explanation:

A student wants to calculate the heat gained of 100 grams of water in order to
calculate the specific heat of a metal in the following problem. The water is
heated from 25C to 50C when the metal is added. The specific heat of water is
4.18 J/gºC. Use Q=m xCxT*

Answers

The quantity of heat gained to raise the temperature from 25.0°C to 50.0°C is 10,450 Joules.

Given the following data:

Mass of water = 100 gramsInitial temperature = 25.0°CFinal temperature of water = 50.0°CSpecific heat capacity of water = 4.18 J/g°C

To find the quantity of heat gained:

Mathematically, heat capacity or quantity of heat is given by the formula;

[tex]Q = mc\theta[/tex]

Where:

Q represents the heat capacity or quantity of heat.m represents the mass of an object.c represents the specific heat capacity.∅ represents the change in temperature.

Substituting the values into the formula, we have:

[tex]Q = 100(4.18)(50 - 25)\\\\Q = 418(25)[/tex]

Quantity of heat = 10,450 Joules.

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An element X exists in three forms A, B and C in the ratio 1:2:3. If C has 10 protonsand the number of neutrons in A, B and C are 10, 11 and 12 respectively,Give the following:(i) Representation of form C of the element X(ii) Electronic configuration of form B of the element(iii) Calculate the average atomic mass.

Answers

x21 +ANSWER

(i) Ne-22

(ii)1s2s22p6

(iii)21.3

An element X exists in three forms A, B and C in the ratio 1:2:3. If C has 10 protons and the number of neutrons in A, B and C are 10, 11 and 12 respectively,Give the following:(i) Representation of form C of the element X(ii) Electronic configuration of form B of the element(iii) Calculate the average atomic mass.

(i)C  has 10 protons and 12 neutrons so a mass of 10 +12 =22

element 10 is Neon (Ne) so this isotope is Ne-22

(ii) they all have the sane atomic number so the same number of electrons

with an electronic structure of 1s2s22p6

(iii) A weighs 20, B weighs 21, C weighs 22

the ratio is 1:2:3

weighted average weight is therefor

(1X20 +2X21 +3X22)/6 =21.3

PLEASE HELP!!
What kind of metal is Co?
Alkali Metal
Transition Metal
Alkaline Earth Metal

Answers

Answer:

I believe Cobalt is a Transition Metal.

Answer:

answer is transition metal

Pls help!!! for 100 points, please only answer if your actually going to help ! A kitten has a mass of 1582 g and accelerates at 1.7 m/s^2. What is the net force acting upon the kitten?
Write down all the givens from the problem.

Are all of the units in the form required to use the generic equation? If not, then show your conversion.

Write the generic equation (equation with variables only) for this problem. Do not add any spaces between letters or symbols.

Substitute your numbers into the generic equation. This is where you show your math work, step by step. Solve the problem

Enter the numeric portion (numbers only) of your answer here rounded to the nearest tenth.

Enter the numeric portion (numbers only) of your answer here rounded to the nearest tenth.

Answers

Answer:

2689.4

Explanation:

PlEASE HELP MEEEE ASAP 50 PTS


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) + 2H20m - 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

Yes,I agree that it is a redox reaction.

In the given reaction potassium metal is placed in water and when a reactive metal is placed in water, it reacts with water to form metal hydroxide and hydrogen gas, as a result, potassium hydroxide and hydrogen gas are produced in the reaction.

A redox reaction is a reaction in which a substance is oxidized during the reaction whereas some other substance is reduced during the reaction, simultaneously.

The given chemical reaction is:

2K(s) + 2H20(l) arrow 2KOH(aq) + H2(g)

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Answer:

In the given reaction potassium metal is placed in water and when a reactive metal is placed in water, it reacts with water to form metal hydroxide and hydrogen gas, as a result, potassium hydroxide and hydrogen gas are produced in the reaction.

Explanation:

Balance the equation: H2O2 → H2O + O2

Answers

Answer:

2H+0 =H2O

Explanation:

May this help you

The atomic number of an element:

#1. Tells you the mass of the atom

#2. Tells you the number of energy levels there are around the atom

#3. Tells you the identity of the atom

#4. Tells you how many valence electrons the atom has

Answers

Answer:

I think #3 might be the answer .

Because in #1 atomic mass tells mass .

#4 Atomic number doesnot only tell about the electrons atom has

Someone help me with this I will make you brain

Answers

I believe the answer is D: To show how using a list of examples can strengthen a claim. Dr. King is using these examples to help support his claim, which will help to strengthen it. I hope this helps :)

what is a molecule?
HELPPP

Answers

Answer:

a molecule is a group of atoms/elements bonded together

14. The following are a list of the four parts of John Dalton's atomic theory Indicate which of
the parts have been modified and why.
1. All matter is made of tiny, indivisible particles called atoms
2. All atoms of an element are identical and all atoms of different atoms are different
3. Atoms of one element cannot be turned into atoms of another element.
4. All atoms combine with one another in fixed whole number ratios.

Answers

Answer:

1

all matter is made of tiny particles called atom

Suppose you've just heard an opera singer warm up her voice. Write your own science question about the sounds a singer makes.

Answers

1. how does warming up help?
2. what does warming up do?
3. what would happen if you don’t warm up?

NEED HELP ASAP! Write a statement explaining your claim about whether or not the equation is correctly balanced.
Then, provide evidence that supports your claim about whether or not the equation is correctly
balanced. Next, connect your evidence to your claim about the equation.

Answers

Answer:

I think that it it correctly balanced that is my opinion and, because  the way it is set up, that the answer will tell you weather or not it is correctly balanced or not.

Evaluating the number of atoms of each element on the product and reactant side, we can conclude that the student's equation isn't balanced.

Given the chemical reaction :

[tex] Al_{4}C_{3} + 6H_{2}O ---> 3CH_{4} + 4Al(OH)_{3} [/tex]

For a balanced equation, the number of atoms of each element in the product side must be equal to that on the reactant side.

Number of hydrogen :

Reactant side = (6 × 2) = 12

Product side = (6 × 2) + (6 × 2) = 12 + 24 = 24

Product side ≠ reactant side ; Hence, the equation isn't balanced

The balanced equation for the reaction goes thus :

[tex] Al_{4}C_{3} + 12H_{2}O ---> 3CH_{4} + 4Al(OH)_{3} [/tex]

Reactant side :

Al = 4

H = (12 × 2) = 24

O = 12

C = 3

Product side :

H = (6 × 2) + (6 × 2) = 12 + 24 = 24

Al = 4

O = 4 × 3 = 12

C = 3

Therefore, the student's equation isn't balanced, the balanced version of the equation has been given .

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which of the following is a pure substance
1 heterogenous mixture
2 homogenous mixture
3 solution
4 element

Answers

Answer:

2 homogenous mixture

Explanation:

the positon of hydrogen is conversial in mendleevs perodic table give reason​

Answers

the position of hydrogen is controversial in periodic table because hydrogen is the only element with out neutron. it belongs to 1 st group but it is not placed there .

Answer:

the position of hydrogen is controversial in periodic table because hydrogen is the only element with out neutron. it belongs to 1 st group but it is not placed there .

Explanation:

What is the Golgi body made of?
O integral proteins
O large steroids
O RNA
O the same thing as the cell membrane

Answers

Explanation:

integral proteins...nns

What does the graph show about the rate of temperature change over time?

Answers

Answer:

The temperature is the same overtime.

Explanation:

Since the line on the graph is straight the temperature will be constant.

Someone pls help me I will make you brain

Answers

Answer:

Carbon Monoxide- D)

Nitrogen Oxides- A)

Particulate matter- C)

Sulfur Oxides- B)

Explanation:

Answer is 100% verified

Count on me, I'm a Chemistry Guru

Read that From picture and tell me the answer please​

Answers

Answer:

1g Hydrogen

Explanation:

Getting to the equation:

Calcium in water reacts vigorously to give a cloudy white Precipitate (compound) called Calcium hydroxide alongwith the evolution of Hydrogen gas.

[tex] \boxed{ \mathsf{Ca + H_2O \rightarrow Ca(OH)_2 + H_2}}[/tex]

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Balancing the equation:

This reaction is not in it's balanced form! The number of atoms of Hydrogen on the left is 2 while that on the right is 4,I.e.,they're not equal.

Adding a 2 in front of H2O solves the problem by making the number of atoms of each element on both the sides equal.

[tex] \mathsf{Ca +2 H_2O \rightarrow Ca(OH)_2 + H_2}[/tex]

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Observations:

Looking into the equation more carefully, we see:

1 atom of Calcium reacts with 2 molecules of water to give 1 molecule of Calcium Hydroxide alongwith 1 molecule of Hydrogen gas.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Gram atomic and molecular masses

Mass of one atom of Calcium = it's gram atomic mass

= 40 g

Mass of one "molecule" of Hydrogen

= it's Gram molecular mass

= gram mass of one atom × number of atoms in one molecule

= 1 × 2

= 2 g

So,

according to our observation:

One atoms of Calcium gives one molecule of Hydrogen (during the particular reaction)

=> 40g of Calcium gives = 2g of Hydrogen

•°• 1 g of Calcium gives = [tex] \frac{2}{40} [/tex]

= [tex] \frac{1}{20} [/tex] g Hydrogen

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Answer:

We're provided with 20g of Calcium,

=> 20g of Calcium gives = 20 × [tex] \frac{1}{20} [/tex] g H2

= 1 g H2

_______________

Hope this helps!

in an oxidation-reduction reaction, how is the reducing agent changed?

Answers

Explanation: The additional terminology comes from the definition that, within redox processes, a reductant transfers electrons to an oxidant; hence, the reductant (reducing agent) loses electrons, so is oxidized, while the oxidant (oxidizing agent) gains electrons, so is reduced.

In an oxidation-reduction reaction, the reducing agent loses electrons and loses potential energy, Therefore, option (C) is correct.

What is a reducing agent?

A substance that loses its electrons in a redox reaction to other substances and gets oxidized is called a reducing agent. A reducing agent is one of the reactants which reduces the other reactant by donating the electrons to the reactant of an oxidation-reduction reaction.

If the reducing agent can't pass electrons to another reactant in a reaction, then the reduction process does not occur and the reaction cannot proceed.

In redox reactions, when an electron loses potential energy as a result of the transfer and energy is released. Electrons with more potential energy are associated with less electronegative atoms and less potential energy is associated with a more electronegative atom (such as O).

Therefore, the reducing agent loses electrons and loses potential energy in a redox reaction.

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Your question is incomplete, but probably the complete question was,

In an oxidation-reduction reaction, how is the reducing agent changed?

(A) it gains electrons and gains potential energy

B) it gains electrons and loses potential energy

C) it loses electrons and loses potential energy

D) it loses electrons and gains potential energy

plz help fast. Which of the following represents a chemical change? (2 points)

1. decomposition of stone due to acid rain

2. iron's attraction to a magnet

3. the pink color of a rose

4. rocks being smoothed by rapid water movement

Answers

Answer:

1. Decomposition of stone due to acid rain.

3. The pink color of a rose.

Explanation:

Chemical changes always end up with new products in an equation, or it has always something to do with chemicals. Physical changes on the other hand, do not result in new products and it just changes the physical properties and physical state of matter of the object.

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