Which of the following is true about pure substances? A. A pure substance has the same chemical properties throughout. All pure substances are unable to be separated by any means. c. A pure substance can only be made up of one kind of atom. D. A pure substance can always be separated by physical means.​

Answers

Answer 1

Answer:first one

Explanation:

Answer 2

A pure substance has same chemical properties throughout , it cannot be  separated by any means and it is made up of one kind of atom.

What are chemical properties?

These properties are defined as those properties which become evident during or after a chemical reaction after the identity of the substance is changed during chemical reaction.

These properties cannot be determined externally just by viewing the substance ,these change immensely after a substance undergoes a chemical change.These are used for identification of unknown substances and for building up chemical classifications.

The major chemical properties are flammability,toxicity,reactivity,acidity and heat of combustion.For a chemical property to be apparent , it is necessary that the structure of the substance is altered.

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Related Questions

Which indicates that thermal energy is no longer being transferred from boiling water to a mug?

The mug and the water lose all thermal energy.
The water is hotter than the mug.
The mug is hotter than the water.
The water and the mug are the same temperature.

Answers

Answer:

Which indicates that thermal energy is no longer being transferred from boiling water to a mug?

The mug and the water lose all thermal energy.

The water is hotter than the mug.

The mug is hotter than the water.

•The water and the mug are the same temperature.

Explanation:

answer #D is correct

When the water and the mug are at the same temperature then thermal energy will no longer be transferred from the boiling water to the mug. Therefore, option (D) is correct.

What is thermal energy?

Thermal energy is generated in a substance when an increase in temperature causes atoms and molecules to move at a faster speed and result in the molecules colliding with each other. The energy generated from the temperature of the heated material is called thermal energy.

Thermal Energy or internal kinetic energy is because of the random motion of molecules in the system. The thermal energy of any system is directly proportional to its temperature.

The more the temperature of the system, the more the movement of molecules within a given system, and the more the thermal energy of the system.

The thermal energy will be transferred from the boiling water to the mug when the water is hotter than the mug. When both have the same temperature then the thermal energy is no longer being transferred from boiling water to a mug.

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What metal is Potassium (K)?

Answers

Explanation:

Potassium is a chemical element with the symbol K and atomic number 19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure

Answer:

alkali metal

Explanation:

Potassium is a chemical element with symbol K and atomic number 19. Classified as an alkali metal

50 POINTS: PLEASE ANSWER AS QUICK AS POSSIBLE!

Question:

After getting their results in, a group of scientists went back and looked at their study. As planned, their experiment consisted of three groups. The first group received a new medicine at a normal dose, the second group received the medicine at half the dose, and the third group received the medicine at twice the dose.

Which of the following best describes what went wrong with the scientists’ study?


Choices:

- an improper experimental procedure

- the lack of a control group

- selection bias

- human error

Answers

Explanation:

The lack of a control group

The answer would be “the lack of a control group.” To make the results more accurate, the scientists should have used a placebo group to use as a comparison.

How many protons, electrons and neutrons do A nitrogen atom with atomic number 7 and mass number 14

Answers

Answer:

p =7

e = 7

n = 7

Explanation:

proton = atom number

electron = atom number - muatan

neutron = mass nimber - atomic number

There are two types of physical changes and chemical reactions- endothermic and exothermic. On the diagram below, which picture (A or B) is endothermic and which picture (A or B) is exothermic? Be sure to explain your reasoning for both.

Answers

Answer:

it is b because its releases heat in to all directions and not b because it staying inside and not releasing anything :)

Explanation:

Answer:

In ice cube heat is taken in absorbed it's an endothermic reaction

In fire heat is given out it is an exothermic reaction

Explanation:

Wanna give you one advice

Exit of heat means exothermic and you can memorize it by

The first word of both word exit ;exo

Hope it helps you


Which RNA strand would match with this DNA strand?
AGGCTAAT

Answers

What is the DNA strand? You have not named it.

what is ch2cl2 bond angle?

Answers

Answer:

109.5

Explanation:

It's a tetrahedreal with four bonds

Which statement about aldehydes and ketones is correct?

A) In aldehydes, the carbon is always joined to at least one hydrogen atom.

B)Every ketone molecular formula is unique.

C) Aldehydes are similar to ketones, but their carbonyl group is located in the middle of the carbon chain.

D) In ketones, the carbon of their carbonyl group is bonded with one other carbon.

Answers

Answer:

A) In aldehydes, the carbon is always joined to at least one hydrogen atom.

Explanation:

Aldehydes and Ketones are organic compounds.

The main difference between them is that aldehydes have the carbon atom attached to at least one hydrogen atom.

In ketones, the carbon is attached to another carbon.

The IUPAC names of alkanals usually end with -eFor alkanones usually end with -one

To reiterate, the striking difference between the two families is that in alkanals, a hydrogen atom is directly attached to the carbonyl group while in alkanones, no hydrogen atoms is attached to the carbonyl group but two bulky alkyl groups.

Oxygen atoms have six outer electrons

Write the symbol for an oxide ion.

Answers

Answer:

[tex]O^{2-}[/tex] is the symbol for an oxide ion

Chemistry Data Analysis --
7.86 x 10^-15 x 3.9 x 10^-10​

Answers

Answer:

3.065 x 10^-24

Explanation:

hope this helps

A metal object has a density of 2 g/ml. When placed in a graduated cylinder with 500 ml of water, the
water rises to 508 ml. What is the mass of the metal object?

Answers

Answer:

The answer is 16 g

Explanation:

The mass of a substance when given the density and volume can be found by using the formula

mass = Density × volume

From the question

density = 2 g/ml

volume = final volume of water - initial volume of water

volume = 508 - 500 = 8 mL

We have

mass = 2 × 8

We have the final answer as

16 g

Hope this helps you

the boiling point of ethanol is 78.40 C. A student conducts an experiment and finds a boiling point of 75.70 C. What is the student's
percent error ?

Answers

Answer:

3.40% corrected to 1dp

Explanation:

78.4-75.7=2.7

percentage error = error/original value× 100

= 2.7/78.40×100

= 3.44387755102040

= 3.40% corrected to 1dp

What is hydrochloride acid plus water plus salt and water

Answers

ANSWER:

It is called Caffeine Hydrochloride.
Formula: HC8H10N4O2Cl

The volume of a candy bar is 55cm^3. The mass of the candy bar is 70g. What is the density of the candy bar in g/cm^3

Answers

Answer:

1.3 g/cm3

Explanation:

Aquanauts explore the area called?

Answers

Answer:

Inner space

Explanation:

I hope this helps

what does CER mean for science?

Answers

Explanation:

Claim, Evidence, Reasoning (CER) model, an explanation consists of: A claim that answers the question. Evidence from students' data. Reasoning that involves a rule or scientific principle that describes why the evidence supports the claim.

PLEASE HELP!

Why do atoms share electrons in covalent bonds?

A. to attain a noble-gas electron configuration

B. to become more polar

C. to become ions and attract each other

D. to increase their atomic numbers​

Answers

Answer:

Answer Option A) To attain a noble-gas electron configuration.

Explanation:

Correct answer from test

Taking into account the definition of covalent bond and octet rule, the correct answer is option A.  Atoms share electrons in covalent bonds to achieve a noble gas electron configuration.

The covalent bond is the chemical bond that occurs between atoms of non-metallic elements. These atoms have many electrons at their outermost level and have a tendency to share them to acquire the stability of the noble gas electronic structure. In this way a molecule is formed.

The tendency of the elements to reach a stable configuration is known as the octet rule. For this, the octet rule explains that there must be eight electrons in their last energy levels, thus acquiring the structure of a noble gas.

So, a covalent bond is a force that joins two atoms of non-metallic elements to form a molecule in order to comply with the octet rule.

Finally, the correct answer is option A.  Atoms share electrons in covalent bonds to achieve a noble gas electron configuration.

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Based on the Phase Change Graph below, what is the Melting Point for this point
substance?

Answers

Answer:

Where is the phase melting graph? Can't seem to find it

Two compounds of phosphorus and fluorine have the following
mass ratios.
Compound 1: 10.14 g fluorine for every 3.38 g phosphorus
Compound 2: 8.42 g fluorine for every 4.21 g phosphorus
Find the whole number ratio of masses of fluorine in compound
1 to compound 2.

Help me please

Answers

Answer: 3:2

Explanation: (10.14÷3.38)÷(8.42÷4.21)=1.5=3/2

What is Mercury's proximity to the sun
PLEASE HELPP

Answers

Answer:

46.943 million km

Explanation:

From an average distance of 36 million miles (58 million kilometers), Mercury is 0.4 astronomical units away from the Sun.

From an average distance of 36 million miles (58 million kilometres), Mercury is 0.4 astronomical units away from the Sun.

(I hope this helped ^^)

I need help in chemistry!!!!!!!!!!!

Answers

Answer:

ok whats the question dude just ask :PPPPPPPPPPPPPPPPPPPPPP

OTHERWISE EOEOEEOEOEOOEOEOEOEOEOOEOWOWOWOWOW

wow is mom upide down

Explanation:

This is the answer hope you see it clear :)

In science class, a student is given a copper cylinder to investigate. The student measures the mass of the cylinder as 53.76 grams. The
student measures the volume of the copper as 6 cm. Which additional property of the copper can the student determine from these
measurements?

Answers

Answer:

From these two values, i.e. mass and volume, density of the copper cylinder can be calculated.

Formula of density is :

Density = Mass / volume.

Now we have mass: 53.76g and volume 6cm³

Density = 53.76 / 6

Density= 8.96 g/cm³

Which phrase is most similar in meaning to “scientific theory”?
A. a best guess explanation
B. a rigorously tested explanation
C. an opinion of what should happen
D. a mathematical relationship

Answers

Answer:

c

Explanation:

Answer:

A. a best guess explanation

Explanation:

A scientific theory explains why something behaves the way it does and is usually backed up by different sources. They are not speculations and can be proven. Those which are speculations and are not proven are called hypothesis. A scientific theory can also be replaced, if it is found that it does not produce valid results, or if a better theory is proposed which is made of one or more old theories.

please hurry i’m taking a test

Answers

Answer:

im pretty sure its move at a constant rate to the right

3. The nucleus:
a. controls all the cell activities
b. controls only part of the cell
c. does not have any activity​

Answers

Answer:

a. controls all the cell activities.

Thank you ☺️

I need help again LOL.

Answers

Answer:

They require diffrent types of atoms for their makeup I belive is the answer Hope this helps

Explanation: Wow you have a lot a questions XD :D :3

Element: A substance that is made up of only one type of atom. Compound: A substance that is made up of more than one type of atom bonded together. Mixture: A combination of two or more elements or compounds which have not reacted to bond together; each part in the mixture retains its own properties.

i hope this helps

what is biogas, biomass and biodigester​

Answers

Answer:

Biogas is a type of biofuel that is naturally produced from the decomposition of organic waste. When organic matter, such as food scraps and animal waste, break down in an anaerobic environment (an environment absent of oxygen) they release a blend of gases, primarily methane and carbon dioxide.

Explanation:

Biomass is renewable organic material that comes from plants and animals. ... Biomass contains stored chemical energy from the sun. Plants produce biomass through photosynthesis. Biomass can be burned directly for heat or converted to renewable liquid and gaseous fuels through various processes.biodigester is like a mechanical stomach. It is fed with organic material, which is broken down (decomposed) by micro-organisms (bacteria) is an oxygen-free (anaerobic) environment to produce a renewable energy called biogas (methane and carbon dioxide) and other material that is mainly used as fertilizer.

Explanation:

Biogas is a type of biofuel that is naturally produced from the decomposition of organic waste.

Biomass is plant or animal material used for energy production, or in various industrial processes as raw substance for a range of products.

A Biodigester simply means a tank which digests organic material biologically. In this sense, the FilterPod is a biodigester. However, many people think of a biodigester as a tank which digests, anaerobically, without air, organic material and produces methane gas for cooking, lighting and heating ect.

Part 1)
There is a storage container with 5.25 tons of Ammonia (NH3). How many molecules of Ammonia are there?

Answers

Answer:

1.69×10²⁹ molecules.

Explanation:

The following data were obtained from the question:

Mass of Ammonia (NH3) = 5.25 tons

Molecules of Ammonia (NH3) =.?

Next, we shall convert 5.25 tons to grams (g). This can be obtained as follow:

1 ton = 907184.74 g

Therefore,

5.25 ton = 5.25 ton × 907184.74 g / 1 ton

5.25 ton = 4762719.885 g

Therefore, 5.25 tons is equivalent to 4762719.885 g

Finally, we shall determine the number of molecules of ammonia, NH3 in 4762719.885 g. This can be obtained as follow:

From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ molecules. This implies that 1 mole of ammonia, NH3 also contains 6.02×10²³ molecules.

1 mole of ammonia, NH3 = 14 + (3x1) = 14 + 3 = 17 g

17 g of ammonia, NH3 contains 6.02×10²³ molecules.

Therefore, 4762719.885 g of ammonia, NH3 will contain = (4762719.885 × 6.02×10²³) / 17 = 1.69×10²⁹ molecules.

From the calculations made above,

5.25 tons (4762719.885 g) of ammonia, NH3 contains 1.69×10²⁹ molecules.

clarify the following expression s
a.atomic number
b.mass number
c.nucleus​

Answers

Answer:

Atomic number of a chemical element is the number of protons found in the nucleus of every atom of that element.

The mass number, also called atomic mass number or nucleon number, is the total number of protons and neutrons in an atomic nucleus.

The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom.

Which statement about the masses of subatomic particals is true?
A. Electrons and neutrons have similar masses.
B. Neutrons and protons have similar masses.
C. Electrons, protons and neutrons have similar masses.
D. Electrons, protons and neutrons have very diffren´t masses.

Answers

the answer is D, all of them have very different masses
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