Câu 3: Nêu phương pháp hóa học nhận biết các dung dịch không màu sau: (a) HCI, NaOH, H2SO,, NaCl. (b) HNO3. KOH, BaCl. Ca(OH)2. Ba(NO3)2 (c) MgCl2, KCl, CuCl2, FeCl3, FeCl2 (chỉ dùng một thuốc thử). (d) Na2CO3, BaCl2, NaNO3 (chỉ dùng một thuốc thử)

Answers

Answer 1

Answer:

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Related Questions

Find the density of mercury if 205 mL has a mass of 2790 g round your answer to the nearest 0.1 g

Answers

Answer:

13.6g/L

Explanation:

The formula for density is D=m/V

D = Density in grams per liter (g/L)

m = Mass of sample in grams

V = volume of sample in liters

Convert 205mL to Liters as follows:

205mL (1L/1000mL) =0.205L

then simply plug into the equation for density:

2790g/0.205L = D= 13.6g/L

Second ionization energies are always _____ than first ionization energies because the remaining electrons are attracted _____ strongly as the positive charge on the ion increases. A large jump in ionization energies is always observed after the _____ electrons have been removed.

Answers

greater

more

remaining

Why is it difficult to classify dissolving as simply a physical or a chemical change?

Answers

It is difficult to classify dissolving as physical or chemical change because at some point dissolving produce new substance which can not be reversed while at some point no new substances are produced but and the process is reversed.

Physical change is a change in which no new substance is formed and the process is easily reversible. For example, the dissolution of salt in water is a physical change since we can reverse the process to obtain salt and water.

Water + Salt <=> Salt Solution

Chemical change is a change in which new substance is formed and and the process is not reversible. For example, the dissolution of metal in acid is a chemical change since we can not reverse the process to obtain the metal.

Acid + metal —> Salt + hydrogen gas

2Na + 2HCl —> 2NaCl + H₂

Thus, we can see that it is difficult to classify dissolving as a physical or a chemical change.

Learn more: https://brainly.com/question/19210143

Which of the following are considered physical properties of a substance?
Color and odor
malleability and hardness
melting and boiling points
all of the above

Answers

hi <3

the correct option would be all of the above

hope this helps :)

All of the above I’ve answered this question before

What do the nuclei of 1H hydrogen atoms contain?

protons only

electrons and protons

electrons and neutrons

neutrons only

Answers

Answer:

"Protons only"

Explanation:

Hydrogen has one proton in its nucleus. It does have one electron rotating outside of the nucleus, BUT NOT IN THE NUCLEUS. 'A' is the correct answer.

This is an image of ice
cubes made of water. Is
water (or ice) a mixture or a
compound made up of
molecules?
А.
a mixture
В.
a compound made up of molecules

Answers

Answer:

it is a compound made up of molecules

A student conducts an experiment to determine the speed of a toy car at the bottom of a ramp after it is released from different heights on the ramp. The student makes one measurement for each height.

What is one way that the student could improve the experiment?


use a different ramp for each height

perform multiple trials for each release height instead of just one

use a different timer for height

perform one trial for each measurement but use a different car for each height

Answers

Answer:

perform multiple trials for each release height instead of just one

Explanation:

why does the s orbital fill before the p orbital

Answers

Answer:

The s orbital is lower in energy than the p orbital  

Explanation:

S-orbital electrons are simultaneously closer to the nucleus (more stable) and farther from the nucleus (less stable) compared to the corresponding p-orbitals. This makes them favorable to occupy when no p-electrons are present, but less favorable to occupy when p-electrons are present, which is why they are filled first but ionize first.


May someone help me with the answer to this question I’ve been stuck on it

Answers

Explanation:

No, that would be incorrect

Answer:

There arre two main parts of the atom, the nucleus and the orbital rings. The three subatomic particles are contained in each of these, the proton and neutron together in the nucleus and the electrons orbiting in the rings.

Which statement about metals and nonmetals is correct? (1 point)
O Metals and nonmetals can both be found in any column of the periodic table.
O Most metals are a solid under normal conditions, and most nonmetals are a liquid.
O Metals tend to be poor conductors of electricity, while nonmetals are strong conductors of electricity.
O Metals can be hammered into thin sheets, and nonmetals are brittle

Answers

Answer:

The answer is the 4th one

The statement about metals and nonmetals that is correct is: "The  Metals can be hammered into thin sheets, and nonmetals are brittle."

Metals are found mostly towards the left hand side of the periodic table. Non-metal character increases as you move towards the right hand side of the table.

One common property of metals is that they are malleable; this means that they can be hammered into sheets while a common property of nonmetals is that most of them are brittle.

Learn more: https://brainly.com/question/10714037

Is it possible to prove that something is real or true of you can’t directly observe it? If no, why not? If yes, how would you do that?

Answers

Answer:

yes

Explanation:

Anything that is verifiable and repeatable is likely to be true. If not verifiable and repeatable, then it may well be completely false, or at least partially false.

This holds for much more than just religious beliefs. What about political thought? One perfect example was when President Obama was pushing his ACA (Obamacare). His facile claim was that with medical coverage for all, the costs of health care would go down. Because people would take better care of themselves, avoiding those major medical bills. But that's just a banality, right? Just words that sound good. I'm not saying that morally, universal health care is wrong. I am saying, don't assume something to be true just because it sounds good. (Of course, health care costs went up, not down.)

Is it true that if you get your car washed every week, it will last longer and cost you less in the long run? Of course not. But it sounds good. People will nod their heads in mindless, lazy agreement. You'll have a cleaner car, you will most likely pay more, and it may last less long, depending on any number of factors. Exactly the same as health care

Assertion : When the added electron goes to smaller n=3 quantum level, the electron-
electron repulsion is much less.

Reason: The added electron occupies a smaller region of space .

Answers

It is due to low volume of electron that causes large distance between two electrons.

When the added electron goes to smaller quantum level, the repulsive force between two electrons is less because the electron which is added occupies small space due to less volume so there is a large distance between two electrons that leads to less force of repulsion.

If the electron has more volume so it occupies more space and there will more repulsive force between two electrons so that's why we can say that the smaller volume of electron is the reason of less repulsive force.

https://brainly.com/question/24387646

Most electrochemical cells are the site of redox reactions. They contain 2 electrodes, the ______ where reduction occurs and the _______
A. cathode, anode
B. None of these
C. anode, galvanode
D. anode, cathode

Answers

Answer:

A.cathode,anode

Explanation:

positive and negative

pls make me the brainliest

Marta wants to explain how pollution is affecting the biodiversity of a local lake. Which of the following models are most appropriate options to use in her explanation? I. Graph II. 3-D model III. Simulation

Answers

Answer:

Graph models are most appropriate options to explain how pollution is affecting the biodiversity of a local lake.

Explanation:

Marta wants to explain how pollution is affecting the biodiversity of a local lake

For explanation

we have to use the graph because graph only shows the gradual level of of pollution that affect the biodiversity of a lake and water resources.

3D model and simulation is also effective but graph model is is more effective than other

To learn more about pollution refer:

https://brainly.com/question/20782855https://brainly.com/question/12191761

nước tự nhiên là chất hay hổn hợp

Answers

nước tự nhiên là chất đó bạn

9.11 x 10^3 in standard notation?

Answers

Answer:

the right answer is 9110

The right Awnser 9.30 w

is water?
A. a substance made up of two different elements (hydrogen and oxygen)
B. an element

Answers

Answer:

A substance made up of two different elements (hydrogen and oxygen)

Plant and Animal Cells
С
B
F
1 20 points
Which letter represents the brain of the cell?
о B
H
H
Why
E
D
G

Answers

Answer:

Nucleus is known as the brain of the cell.

correct option is B letter

ons below.
Which diagram shows the correct electron
configuration for fluorine (F)?

Answers

Option A is correct way of representation of electronic configuration.

It is option A I think!

How does water vapor in the air change state below the freezing point

Answers

Answer:

Water vapor molecules in the air near the can cooled when energy from the air transferred to the cold can. These water molecules slowed down, condensed to liquid water, and then froze to become ice. Your can might have some water and some ice on the outside of it.

Explanation:

Can someone explain this to me, please?
A stable sodium atom has 11 electrons. The sodium isotope [tex]Na_{24}[/tex] has:
A.) How many protons?
B.) How many neutrons?
C.) An atomic number of what?

Answers

Answer:

Isotopes have same atomic numbers, no. of protons and no. of electrons. Only their no. of neutrons and atomic mass are changed.

Na - 24:

Atomic Mass = 24

Atomic No. = 11

Hence,

No. of protons in Na-24 = 11

No. of neutrons = Atomic Mass - Atomic Number

No. of neutrons = 24 - 11

No. of neutrons = 13

Atomic Number = 11

[tex]\rule[225]{225}{2}[/tex]

Hope this helped!

~AH1807Peace!

mention four states of matter and explain and give examples​

Answers

Answer:

solid: ice.

liquid: water

gas: methane

plasma: lightning

Explanation:

Complete the following sentences by writing in the correct word.

In a neutral atom, the number of electrons must be the same as the number of
.
The subatomic particle in an atom with no charge is the
.
The number of protons in an atom is the
number.
The total number of protons and neutrons in an atom is the
number.

Answers

1)proton number

2)neutron

3)(Z)

4)mass

As a professor Daniel must complete a research project each year in order to
stay on staff. Daniel is an engineer and has to deal with many complicated
mathematical calculations. Knowing this fact Daniel would most likely concern
himself with qualitative research,

Answers

Explanation:

Add our site sources in order to be advantage of knowledge

define mass number in your own words​

Answers

Answer:

The total number of protons and neutrons in the nucleus of an atom is called mass number.

Answer:

mass number also called nucleon number and it's the total number of neutron and proton in an atomic nucleus.

Circle the two terms in each group that are related. Explain how the terms are related.
16. Celsius degree, mass, Kelvin
17. balance, second, mass
18. kilogram, liter, cubic centimeter
19. time, second, distance
20. decimeter, kilometer, Kelvin

Answers

Answer:

16) Celsius degree and Kelvin are related since they are measuring unit of temperature.

(17) Balance and Mass are related since mass can be measured with balance.

18) Liter and cubic centimeters are related since they are used to measure capacity or volume of liquid.

19) time and second are related since time is measured in second

20) decimeter and kilometer are related since they are measuring unit of distance or displacement.

Explanation:

The two terms in each group that are related are Celsius and Kelvin, balance and mass, liter and cubic centimeter, time and second, and decimeters and kilometers.

What are Celsius and Kelvin?

Celsius and Kelvin are the units and they are related to each other because both of them can be used to determine or to define the temperature of the environment for anything which is needed to be measured.

The balance and mass are related to the balancing of mass and kilogram with centimeter cubic are related for density and time and second is related to each other last decimeters and kilometers unit of lengths.

Therefore, two terms in each group that are related are Celsius and Kelvin, balance and mass, liter and cubic centimeter, time and second, and decimeters and kilometers.

Learn more about Celsius and Kelvin, here:

https://brainly.com/question/14618997

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grass → rabbit → fox

Explain why energy is lost by the rabbits in the middle step of this food chain.

Answers

Answer:

The rabbit losses energy by great and waste

Explanation:

The grass loses energy by respiration and a rabbit from eating other living organisms but when the fox eats the rabbit no if not little energy is passed to the fox

where do we get the mass number​

Answers

Explanation:

Mass number is the sum of the numbers of protons and neutrons present in the nucleus of an atom.

What is the structure of a fluorine atom?

Answers

Answer:

The nucleus consists of 9 protons and 10 neutrons.  Nine electrons occupy available electron shells.

Distillation can be separated in what technique?
A. Chemical
B. Physical

Answers

Answer:

B. Physical process is the way distillation can be separated.

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