Trường hợp nào sau đây là chất tinh khiết

Answers

Answer 1
Sắt, thép và nước là một số ví dụ về một chất tinh khiết. Không khí có thể là một hỗn hợp đồng nhất thường được coi là một chất tinh khiết. Như chúng ta đã biết kim cương, đường sucrose, mật ong và không khí đều là những chất tinh khiết. Nước tinh khiết có hai nguyên tử hydro và một nguyên tử oxy.

Related Questions

answer pls ASAP will mark the brainliest

Answers

First one……………………………….

For me that is the first :

Both the identity and the properties of a substance change.


A car moves with a velocity of 15 m/s west for 3 seconds. Then, the
car moves with a velocity of 15 m/s east for 1 second. What is the
total displacement of the car?

Answers

Answer:

450 metre

Explanation:

VELOCITY = DISPLACEMENT /TIME TAKEN. THEREFORE THE DISPLACEMENT = 450 M.

Explanation:

a reaction is said to be ________ if the bonds formed during the reaction are stronger than the bonds broken.

Answers

Answer:

Exothermic

Explanation:

Bond strength has everything to do with the energy associated with it. What I mean by that, is a stronger bond will require a lot higher of an energy input to break than a weaker bond.

In the same way, energy is released when a bond is made. So, the formation of a stronger bond releases more energy than the formation of a weaker bond.

So, putting the two ideas together, if the bonds formed as stronger than the bonds broken, then more energy is released than taken in, which means energy is released overall over the course of the reaction. This means that the reaction is exothermic.

If there was energy taken in overall, this would be an endothermic reaction.

Let me know if that makes sense, and hope I helped! :)

Exothermic reaction is a reaction in which the bonds formed during the reaction are stronger than the bonds broken.

When chemical reactions occur, there will always be an accompanying energy change.

In exothermic reaction the bonds formed in the products are stronger than the bonds broken in the reactants whereas in endothermic reaction the bonds broken in the reactants are stronger than the bonds formed in the products.

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The formula of alkanes contain 3 5 7 and 9 carbon atoms

Answers

Explanation:

In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carbon–carbon bonds are single.

Nguyên tử nguyên tố sắt có 26e
a. Viết cấu hình e của sắt
b. Sắt thuộc nguyên tố s,p,d,f

Answers

Answer:

1s2 2s2 2p6 3s2 3p6 3d6 4s2

Explanation:

2. Differentiate the types of tectonic plates.

Answers

There are three main types of plate boundaries:

Convergent boundaries: where two plates are colliding. Subduction zones occur when one or both of the tectonic plates are composed of oceanic crust. ...

Divergent boundaries – where two plates are moving apart. ...

Transform boundaries – where plates slide each other.

sorry pag mali ...

Answer:

Convergent boundaries: where two plates are colliding. Subduction zones occur when one or both of the tectonic plates are composed of oceanic crust. ...

Divergent boundaries – where two plates are moving apart. ...

Transform boundaries – where plates slide passed each other.

Explanation:

6. Which of the following is a binary compound?
a. CaCO3
b. CuSO4
c. H2O
d. Pb(NO3)2

Answers

Answer:

The answer to your question is c. H2O

Explanation:

a. CaCO3 ----> Calcium Carbonate is obviously not a binary compound because it contains more than two elements.

b. CuSO4 ----> CuSO4 stands for copper(II) sulfate. Sulfate is the polyatomic ion SO4 -2.

c. H2O ----> Binary molecular compounds are composed of only two elements. Examples are H2O, NO, SF6 etc.

d. Pb(NO3)2 ----> Lead(II) nitrate is an inorganic compound with the chemical formula Pb(NO3)2.

I hope this helps and have a great day!

why are some substances such as magnesium and fluoride allowed in drinking water?

Answers

Answer:Pure water does not contain fluoride, but much drinking water does contain fluoride that is deliberately added to reduce tooth decay of children who drink the water. Some drinking water supplies also contain fluoride naturally.

Explanation:

in small doses not harmful

Fluoride is a chemical that is intentionally added to drinking water in order to prevent tooth decay in children. Pure water does not naturally contain fluoride. Some sources of drinking water naturally contain fluoride as well.

Why magnesium and fluoride allowed in drinking water?

Fluoride is a chemical that is intentionally added to drinking water in order to prevent tooth decay in children. Pure water does not naturally contain fluoride. Some sources of drinking water naturally contain fluoride as well.

Compared to magnesium found in food, magnesium in water is present as hydrated ions, which are more easily absorbed. Thus, the role played by water magnesium in the prevention of magnesium insufficiency may be quite important for people who drink water with high magnesium levels.

To learn more about magnesium and fluoride refer to:

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Using a lamp without a shade and a baseball, Juan turned on the lamp and placed it on one side of a darkened room. He sat on the other side of the room and held the baseball between his face and the lamp.

Based on the model, what would the final step of his model?

Answers

Answer:b

Explanation:

1. ___is the speed and direction of movement.
1 Acceleration
2Density
3Velocity
4Work

Answers

Answer:

VELOCITY

Explanation:

VELOCITY IS THE SPEED AND DIRECTION OF MOVEMENT

Explanation:

velocity

reason: The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time. Velocity is equivalent to a specification of an object's speed and direction of motion (e.g. 60 km/h to the north).

What is the element name for mg2SiO4

Answers

Magnesium silicate I hope this help

Answer:

forsterite

Explanation:

Why is carbon an element and not a compound?
A. Carbon bonds easily with oxygen, but not helium.
B. All carbon atoms have the same number of protons.
o C. All carbon atoms have the same number of neutrons.
.
D. Carbon is found in all living organisms.

Answers

Answer:

Carbon is found in all living organisms.

Answer: d

Explanation: i promise I've took the k-12 test

3. If you drive for 3 hours at a constant speed and make it 400 miles, how fast did you go?​

Answers

Answer:

133.333333333 mph

or

214.5791999994464 kph

Explanation:

Answer:133.333333333 mph

or

214.5791999994464 kph

Explanation:

Why do we use the mole concept ??

Answers

Answer:

Here

Explanation:

Chemists need the mole concept to bridge the gap between the microscopic world of atoms to the macroscopic world of humans. As you know, the molecular level consists of particles that are invisible to us.

Answer:

it allows us to count atoms and molecules by weighing macroscopic amounts of material.

Select the part that contains the information that a plant cell uses for growth and activities.

a. golgi b. vacuole c. chromosomes d. chloroplasts

Answers

The correct answer is C. Chromosomes


Other correct options would be nucleus but since that is not an option, C would be the correct one.

Hope this helps!

The part that contains the information that a plant cell uses for growth and activities is known as Chromosome. Thus, the correct option for this question is C.

What are Chromosomes?

Chromosomes may be defined as thread-like structures that appear during cell division. These structures are present in the nucleus of the cell and are made up of DNA, RNA, histones, and some non-histone proteins.

Chromosomes were first discovered by E. Strasburger in 1875. But the term chromosome was given by Waldeyer in 1888. Ultimately, the nucleus of the cell contains all sorts of genetic information which are essential for the growth and activities of organisms.

The Nucleus contains DNA which is known as the genetic material of most organisms including plants.

Therefore, a chromosome is a part that contains the information that a plant cell uses for growth and activities. Thus, the correct option for this question is C.

To learn more about Chromosomes, refer to the link:

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Predict the ions that form when magnesium(group IIA) and nitrogen (group VA) react:.

Answers

Answer:   Mg²⁺   &  N³⁻

Explanation:

Since Magnesium is in group 2, then it favors losing two electrons forming a cation with a charge of +2 ( Mg²⁺).

Since Nitrogen is in group VA, it favors gaining three electrons forming the anion with charge -3 (N³⁻).

Help meeeeeeeeeeeeeee ​

Answers

this is the answer hope it helps you!!

Question 116 g of sunflower oil is
used in a recipe. The density of the
oil is 0.925 g/mL. What is the volume
of the sunflower oil in mL?

Answers

Answer:  125.41 mL

Explanation:

Volume = mass ÷ density

             =  116 g  ÷  0.925 g/mL

             =  125.41 mL

A 116 g of sunflower oil of 0.925 g/mL has a volume of 125.41 mL.

Which statement about exothermic reactions is TRUE?
A.In an exothermic reaction, energy is absorbed, bonds are broken, and the temperature decreases.
B. In an exothermic reaction, energy is released, bonds are formed, and the temperature increases.

Answers

Which statement about exothermic reactions is TRUE?

A.In an exothermic reaction, energy is absorbed, bonds are broken, and the temperature decreases.

B. In an exothermic reaction, energy is released, bonds are formed, and the temperature increases.

Hydrogen sulfide gas is combusted with oxygen gas to produce sulfur dioxide gas and water vapour. If there is 48.4 L of oxygen available. What volume of hydrogen sulfide gas may be combusted if the pressure and temperature are held constant?

Answers

Answer:

2H2S + 3O2 → 2SO2 + 2H2O

V(O2) = 48.4 L

p = 105 kPa = 1.036 atm

T = 190 + 273 = 463 K

Ideal gas law:

pV = nRT

n = \frac{pV}{RT}n=  

RT

pV

 

R = 0.08206 L×atm/mol×K

n(O2) = \frac{1.036 \times 48.4}{0.08206 \times 463}=1.319 \; mol=  

0.08206×463

1.036×48.4

=1.319mol

According to the reaction:

n(H2S) = \frac{2}{3}  

3

2

​   n(O2) = \frac{2}{3} \times 1.319 = 0.8798 \;mol  

3

2

​ ×1.319=0.8798mol

V = \frac{nRT}{p} \\ V(H_2S) = \frac{0.8798 \times 0.08206 \times 463}{1.036}=32.26 \;LV=  

p

nRT

​ V(H  

2

​  S)=  

1.036

0.8798×0.08206×463

​  =32.26L

Answer: 32.26 L

Explanation:

Why do planets orbit faster as they get closer to the Sun?

The orbit becomes smaller closer to the Sun.
The orbit becomes smaller closer to the Sun.

The eccentricity changes as the planet gets closer to the Sun.
The eccentricity changes as the planet gets closer to the Sun.

The force of gravity increases closer to the Sun.
The force of gravity increases closer to the Sun.

The Sun's magnetism causes a "sling shot" effect.

Answers

Explanation:

The speed at which a planet orbits the Sun changes depending upon how far it is from the Sun. When a planet is closer to the Sun the Sun’s gravitational pull is stronger, so the planet moves faster. When a planet is further away from the sun the Sun’s gravitational pull is weaker, so the planet moves slower in its orbit.

How do the claims in drug ads impact the medical profession in 4 sentence

Answers

Answer:

But drug advertising is not all about deception. It can offer helpful information if you know what to look for. "Advertisements can offer information on drugs that may help many older men, especially those who have conditions that may be tough to treat or manage, such as diabetes and hypertension,"

Someone pls help me I will make you brain

Answers

c-  i and iii

I hope this helps

lol can some have helo me out its easy
1, 2 and 3

Answers

Answer:

1. A

2. C

3. C

Explanation:

1. there are single cell organisms

2. all others are abiotic factors

3. individual is just one, population is one species, community is all populations, ecosystem includes abiotic and biotic factors, biome is a large geographical area.

Which traits does the western harvest mouse have that might be adaptive for the environment where it lives?

Answers

Its tail helps it climb down the tall grasses and lets it swing from the grass like a monkey in a tree

Explanation:

Answer:

Into the adaptive Trait!

Explanation:

Calculate the percent composition by mass of each element in NaClO2.

Answers

Answer: Divide the mass of the first dissolved component by the solution mass, and then multiply the result by 100 to calculate the mass percentage. In our example, the first dissolved compound is NaCl; the mass percent is (10 g / 136 g) x 100 percent = 7.35 percent.

Explanation: its up, look

which group of elements would react with lithium

Answers

Explanation:

lithium has group 1 elements and it valance electron has 1

so it more react with group 7 to be more stable

negative ions form when atoms _______ valence electrons.

Answers

Answer:

Negatively charged ions are called anions, and an anion is formed when an atom gains an electron. Thus, the atom has an extra charge of electrons,

Explanation:

so it becomes negatively charged.

Negative ions (or anions) are atoms that have gained electrons.

Electrons have a negative charge so if an atom is getting more of them, it's becoming more negative.

How do we determine the volume of an irreguler shaped object?

Answers

Answer:

You can measure the displacement when the object is placed in a certain volume of water.

what are 5 different bases for birds

Answers

Answer:

adenine, guanine, cytosine, thymine, and uracil

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