Answer:
When a substance undergoes changes in its chemical composition or combines with another substance to form a new substance is referred to as chemical change. In contrast, physical change is defined as the change in appearance or state of matter and not the chemical composition of the substance.
Explanation:
When a clear liquid is boiled or heated, the kinetic energy of the molecules increases, and the evaporation of the liquid takes place faster. For example, evaporation is a type of physical change, in which the liquid is heated to form bubbles or vapors. These vapors rise in the air and decrease the volume of the liquid. In this process, the liquid has only changed its state of matter (liquid to gas) and not the chemical composition. Thus, there is no chemical change taking place in the heating of water and only physical change is taking place.
Differentiate between. Melting and freezing point. Elements and compounds . Evaporation and condensation. Compound and mixture.
Answer:
Melting poing is the temperature at which a solid changes to liquid under atmospheric pressure. Freezing point is the temperature at which liquid changes to solid under atmospheric pressure.
Elements are substances that are made from one type of atom. An element cannot be broken down into any other substance. ... Compounds are substances made from atoms of different elements joined by chemical bonds. They can only be separated by a chemical reaction.
Compounds are formed because of chemical bonding between two elements. Mixtures are formed when substances are physically mixed with one another. Compounds are basically of three kinds : Ionic, metallic and covalent
We are driving to Orlando. The sign says
that it is 145 kilometers to Orlando.
How many meters is it to Orlando?
A: 0.145
B: 145,000
C: 14.5
D: 14,500
Answer:
b
Explanation:
there is 1000m in 1 km so the ans is literally just 145x1000 m which is 145000m
Answer:
B! 145,000
Explanation:
your welcome love!
What is an atomic number
Answer:
the number of protons is called the atomic number
hope it helps you buddy
Answer: number of protons in an atom
Explanation:
Which of the following symbolic representations of matter signifies a mixture of elements?
Answer:
[tex]{ \sf{A \: and \: C \: \: only }}[/tex]
Can someone plz help me answer this question
Answer:
10 ml
Explanation:
The graduated cylinder contains 19 ml of water before the silver pellet is placed inside. Afterwards, the graduated cylinder measures 29 ml of water. Therefore the pellet displaced 10 ml of water. ( 29ml - 19ml = 10ml )
convert methanol to ethanol
ANSWER:
We can convert methanol into ethanol by an organic coupling reaction which is called Wurtz reaction. This is carried out with sodium metal in the presence of dry ether and forms higher alkanes.
Which choice below represents a negative impact that chemistry has on society?
development of cancer treatment drugs
development of Teflon, the nonstick material used in cookware
combustion of car engines producing pollutants in the air
the development of nuclear power plants used to produce electricity
Answer:
combustion of car engines producing pollutants in the air
When copper is changed to copper(II) nitrate by the nitric acid, it is an example of a(n) ______-_______ reaction. (two words, include the hyphen with no spaces)
Answer:
oxidation- reduction
Explanation:
where gaining electronic reduces one element and losing them oxidize the other nitric acid is not only strong it is also a oxidizing agent
Oxidize: copper = Cu+2When copper is changed to copper(II) nitrate by the nitric acid, it is an example of an oxidation-reduction.
What is molecule?
Molecule is defined as number of atoms combined together, that shows the most smaller chemical compound's fundamental unit that participate in chemical reaction. In the combination of atoms attractive forces play a vital role and it helps to bound the atoms by a chemical bond.
Liquid consist of small range of order and the reason behind this is intermolecular attractive force which is very strong and due to this reason molecules are packed together tightly. Due to presence of high kinetic energy the molecules present in the liquid move rapidly and fastly with one another.
Water is considered to be the simpler molecule and it consist of hydrogen and oxygen atom bounded together and due to the reason of high electronegativity of the oxygen's atom the bonds present are polar as well as covalent. Due to presence of high kinetic energy the molecules present in the liquid move rapidly and fastly with one another.
Therefore, When copper is changed to copper(II) nitrate by the nitric acid, it is an example of an oxidation-reduction.
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The radius of a silver atom is 145 pm. How many silver atoms would have to be laid side by side to span a distance of 2.31
mm?
atoms
M
Given that the radius of a silver atom is 145 pm, it would take [tex]7.97 \times 10^{6}[/tex] silver atoms laid side by side to span a distance of 2.31 mm.
The radius of a silver atom is 145 pm. Then, the diameter (twice the radius) is:
[tex]d = 2 \times 145 pm = 290 pm[/tex]
We will convert 290 pm to millimeters. We will use the conversion factors:
1 m = 10¹² pm1 m = 10³ mm[tex]290 pm \times \frac{1m}{10^{12}pm } \times \frac{10^{3}mm }{1m} = 2.90 \times 10^{-7} mm[/tex]
If the diameter of 1 silver atom is 2.90 × 10⁻⁷ mm, the number of silver atoms required to span a distance of 2.31 mm is:
[tex]2.31 mm \times \frac{1Ag\ atom}{2.90 \times 10^{-7}mm } = 7.97 \times 10^{6} Ag\ atom[/tex]
[tex]7.97 \times 10^{6}[/tex] silver atoms span a distance of 2.31 mm.
You can learn more about unit conversions here: brainly.com/question/19420601
Using the ruler, what is the value of A considering significant
figures?
Answer:
13.7 cm
Explanation:
If the number is between two whole numbers then that means it is going to be a decimal, how to determine the decimal is by how many ticks/lines are between it, so if you count from 13 cm and count each line as 1 you get to the number 7 and since that number is between the whole number it becomes 13.7
Which type of model best represents crystals?(1 point)
ball-and-stick
ribbon
Lewis dot
space-fill
Which option describes the molecule geometry of a molecule with one bond and three lone pairs?(1 point)
angled
octahedral
tetrahedral
linear
Answer: angular
Explanation:
Angular and is found in hydrogen...from sighwell assumption saying that is they is three pairs of electrons in the valence shell of the central atom the orbital will oriente at an angle of 120° to form a bond of trigonal planar or angular.
Answer:
1) ball and stick is right just did this on my test.
2) linear
Explanation:
Why non quantitative observation are not useful?
Quantatative is when a number of something changes, and we could sometimes visualize it, but qualitative is different.
Hope this helps
kenny
:D
Anti coagulant usend in blood sampling
Answer:
Ethylenediaminetetraacetic acid (EDTA), heparin, and citrate are the most commonly used anticoagulants (39–41). pls mark me branilest
Anyone know the answer ?
The correct answer is: Avogadro
The Avogadro constant (NA or L) is the proportionality factor that relates the number of constituent particles (usually molecules, atoms or ions) in a sample with the amount of substance in that sample. Its SI unit is the reciprocal mole, and it is defined as NA = 6.02214076×1023 mol−1.
The answer is Avogadro.
Explanation:
Here are the examples :
The mass of a single carbon-12 atom has been found to be 1.992×10^-23 g using a mass spectrometer. The number of atoms in exactly one mole of 12C is 6.02×10^23. This can be shown by the following calculation.
Na = Mass per mole of 12C ÷ Mass of one atom of 12C
= 12g/mol ÷ 1.992×10^-23
= 6.02 × 10^23 mol^-1
Thus one mole of any substance contains 6.02×10^23 particles. This number is called the Avogadro constant.
So that 12g of the element carbon , 1 g of the element hydrogen and 32g of the element sulphur contains 6.02×10^23 atoms even though the element carbon exist as atoms, and Hydrogen and sulphur exist as molecules.
I hope it can help you
What is the reason for the emission of light after the gas in a discharge tube is excited?
A)
photo-electric emission
Eliminate
B)
spontaneous radioactive reaction
C)
energy jumps by electrons due to excitation
D)
high energy reaction of the gas inside the tube
Answer:
c
Explanation:
took test on usa testprep
When gas in a discharge tube is excited to higher energy level after some seconds they return to the ground level by releasing energy in the form of light. Thus energy jumps by electron due to excitation is correct option.
What is gas discharge tube?A gas discharge tube is an electronic devise containing inert gases that ionizes and conducts results in emission of light.
When a potential is applied between the electrodes in a gas discharge tube, and the pressure is reduced, the gas particles inside forms a plasma of ions.
The electrons released when excited to higher energy level by absorbing energy and returns to the initial state by emitting energy in the form of light, the discharge tube glows.
The color emitted by the discharge tube vary based on the gas in the tube. Each type of gaseous ions emit different colors.
Therefore, the light emission in gas discharge tube is due to energy hike during electron excitation and then relaxing by emitting the light energy. Thus, option c is correct.
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What are the limitations of using chemical indicators in determining the pH of a given solution?
Answer:
1) chemical indicators won't work above it's pH range so therefore it probably won't change colour.
2) the solution should be clear and colourless to see colour change.
3) indicators tend to be of low accuracy so it's not 100% reliable.
A student was adding NaOH to two different acid solutions, HCl and HF, until a pH of 7 was reached in both solutions. The acids had the same initial volume, and both had an initial pH of 4.5. Which statement is true regarding the amount of NaOH added to each acid?
Which one is the strongest acid?
•Formic acid
•oleic acid
•Malnoic acid
•None
(3.6 x 104) / (4 x 10-6)
Answer:
930 pls mark me branilest
Answer:
11.0117647
Explanation:
Describe what each letter and number
means in the chemical formula below.
C.H₂O
Answer: c is carbon h is hydrogen with the 2 means 2 hydrogen and o is oxygen
In conclusion alphabets represent elements and numbers represent how many elements
Difference between heavy chemicals and fine chemicals
Answer:
Fine chemicals are used as starting materials for specialty chemicals, particularly pharmaceuticals, biopharmaceuticals and agrochemicals. ... The term "fine chemicals" is used in distinction to "heavy chemicals", which are produced and handled in large lots and are often in a crude state.
Explanation:
Answer for this one?
Cu2+ is the correct answer!
Please help ASAP!!!!!!!
Answer:
Chemists develop safer and more effective fertilizers and pesticides .Chemists develop more productive and safer crops .Explanation:
Agriculture means food producingIdentify which subatomic particles match each of these descriptions. One of the descriptions describes two particles. Make sure to include both particles it describes. Description Particle(s) have a relative charge of +1 have a relative charge of -1 have no charge located in the nucleus of an atom have a much lower mass than the other two types of particles Answer Bank protons electrons neutrons
Explanation:
protons have a relative charge of +1, they are located in the nucleus and the carry a positive charge
the electrons are negatively charged and have a charge of -1 . They are found orbiting on the shells .the electrons have a negligible mass of 1 / 1840
the neutrons have no charge they are located in the nucleus of an atom .
The factor in an experiment that is being tested and measured is known as the:
Answer:
The dependant variable
Explanation:
The dependent variable is the factor that is being tested and measured in an experiment.
I’m so confused somebody help lol
Answer:
lol☺️☺️☺️☺️☺️☺️☺️☺️
HELPPP!!!
11) An international set of units which are used in Science and based on the Decimal System A. Basic Units
B. Derived Units
C. Metric (SI) Units
D. English (Common) Units
E. Random Errors
12) Standard units that can actually be measured with an instrument or device
A. Basic Units
B. Derived Units
C. Metric (SI) Units
D. English (Common) Units
E. Random Errors
13) An older system of units, still used in USA for commerce and construction
A. Basic Units
B. Derived Units
C. Metric (SI) Units
D. English (Common) Units
E. Random Errors
14) Mistakes due to carelessness or lack of verification
A. Basic Units
B. Derived Units
C. Metric (SI) Units
D. English (Common) Units
E. Random Errors
15) units that must be calculated from measured values
A. Basic Units
B. Derived Units
C. Metric (SI) Units
D. English (Common) Units
E. Random Errors
Answer:
11. A
12. B
13. D
14. E
15. C
Which statement correctly compares the number of protons and electrons in atoms of rubidium (Rb) and calcium (Ca)?
(1 point)
Rubidium has more protons and fewer electrons than calcium.
Rubidium has fewer protons and more electrons than calcium.
Rubidium has more protons and more electrons than calcium.
Rubidium has fewer protons and fewer electrons than calcium.
Answer:
Chemical elements are categorized in the Periodic Table based on the number of protons and electrons. The electrons are the sub-atomic particle, which revolves around the atomic nucleus and has a negative charge. The protons are the positive charged sub-atomic particles, which are present in the nucleus of the atom.
Explanation:
The chemical element is a pure particle, which is made up of atoms. The atoms in a neutral chemical element have the same number of electrons and protons. In the case given above, calcium has fewer protons and electrons than rubidium. Calcium has the atomic number 20, such that it belongs to group 2 and period 4. The number of electrons and protons in calcium (no net charge) is 20. Similarly, the rubidium belongs to group 1 and period 5. The element has the atomic number 37, such that the number of electrons and protons in rubidium is 37.
Latanya brown is a nine-year old african american who is hospitalized with acute sickle cell crisis. the pharmacist is preparing intravenous fluids for this patient. she adds 2 grams of potassium chloride to 1 l of d5w/1/2 normal saline. what is the estimated osmolarity per liter (mosm/l) of this solution assuming the final volume is 1L (mw of sodium =23, potassium=39, chloride=35.5, and dextrose is 198)?
Answer:nb mhvj
Explanation:
hvvmjhv
How many names make up binomial nomenclature?
A(3)
B(4)
C(1)
D(2)
