What do these two changes have in common?
using a large magnet to remove pieces of iron from a junkyard
rain forming in a cloud
Select all that apply.
Both are caused by heating.
Both are only physical changes.
Both conserve mass.
Both are chemical changes.
Answer: Both are only physical changes.
Explanation:
Both are only physical changes.
• The material, which takes part in the change is structurally similar after and before the change is known as the physical change.
• The cloud formation is a physical change as when evaporation of water takes place it goes into the air and produces cloud by the process of condensation. The same water goes back to earth by the process of precipitation and this get repeated again and again.
• A chemical change takes place when formation of new substance takes place by combining two substances. In the case, when a magnet picks up iron in a junkyard, one is still having an iron and a magnet, no formation of substance is taking place. So it is a physical change.
Thus, both the given processes are examples of only physical changes.
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what are the strengths and weaknesses of the Mendeleev periodic table?
Answer:
Advantages:
1. Grouping of elements. He generalized the study of the elements then known to a study of mere 8 groups.
2. Gaps for undiscovered elements. Mendeleev left some gaps in his periodic table. These gaps were left for subsequent inclusion of elements not known at that time. He correctly thought that such elements would be discovered later.
3. Prediction of properties of undiscovered elements. He predicted the properties of then unknown elements om the basis of properties of elements lying adjacent to the vacant slots.
4. Incorrect masses corrected. He was able to correct the values of atomic mass of elements like gold and platinum by placing these elements strictly on the bases of similarities in their properties.
Disadvantages:
1. Anomalous pairs: Argon with atomic mass 39.9 precedes potassium with atomic mass 39.1.
Cobalt with atomic mass 58.9 precedes nickel with atomic mass 58.6.
Tellurium with atomic mass 127.6 precedes iodine with atomic mass 126.9.
2. Position of isotopes: According to Mendeleev's periodic law, isotopes of an element must be given separate places in the periodic table since they have different atomic masses. But they were not assigned separate places.
3.Grouping of chemically dissimilar elements: Elements such as copper and silver bear no resemblance to alkali metals but they have placed in separate groups.
4.Separation of chemically similar elements: Elements that are chemically similar, such as gold and platinum have been placed in separate groups.
5.Electron arrangement: It does not explain the electron arrangement of elements.
6. Position of Hydrogen: It was not given in a fixed position.Explanation:
The Mendeleev periodic table has strengths in its predictive power, organization of elements, and observation of periodic trends. However, it has weaknesses in incomplete representation, limited understanding of atomic structure, and challenges in placing rare earth elements.
The Mendeleev periodic table, developed by Dmitri Mendeleev in the 19th century, laid the foundation for the modern periodic table. It has several strengths and weaknesses, which are outlined below:
Strengths of the Mendeleev periodic table:
Predictive Power: One of the major strengths of the Mendeleev periodic table is its ability to predict the existence and properties of yet-to-be-discovered elements. Mendeleev left gaps in the periodic table, accurately predicting the properties of elements that were later discovered and filled in those positions.
Periodic Trends: The Mendeleev periodic table organizes elements in a way that allows for the observation of periodic trends. Elements within the same group (vertical column) exhibit similar chemical properties and have similar valence electron configurations. This periodicity helps in understanding the behavior and reactivity of elements.
Classification of Elements: The Mendeleev periodic table classifies elements based on their atomic number and chemical properties. It provides a systematic arrangement of elements, allowing scientists to organize and study them more efficiently.
Weaknesses of the Mendeleev periodic table:
Incomplete Representation: The Mendeleev periodic table, when initially proposed, had gaps for undiscovered elements. While Mendeleev made accurate predictions, some of the gaps were filled in later with elements that did not necessarily match the properties initially predicted. This incomplete representation can be seen as a weakness.
Limited Understanding of Atomic Structure: At the time of Mendeleev's development of the periodic table, the understanding of atomic structure was incomplete. The periodic table was based on elemental properties without the knowledge of atomic numbers or the electron configuration of elements. This limitation hindered the ability to explain certain observed trends and properties accurately.
Lack of Internal Structure: The Mendeleev periodic table did not provide a detailed understanding of the internal structure of atoms or the arrangement of electrons in energy levels. It primarily focused on organizing elements based on their chemical properties and atomic weights, lacking the underlying atomic structure information.
Rare Earth Element Placement: Mendeleev faced challenges in placing the rare earth elements in the periodic table. Initially, he grouped them together as a separate series, but later refinements led to the placement of the rare earth elements within the main body of the table. The difficulty in organizing these elements reflects a weakness in the early understanding of their properties and arrangement.
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Which element has four times as many protons in its nucleus than are found in Neon?
Answer:
Zirconium, Zr, 40
Explanation:
Protons can be found by looking at the atomic number. Neon's atomic number is 10, so just multiply 10 by 4 and you get 40.
Match each label below with the appropriate term. Note: there may be more than one correct answer.
nonbonding electrons
sigma bond
represents two electrons
Answer: sigma bond
Represents two electrons
Explanation:
E2020
Answer:
Sigma Bond AND Represents two electrons.
Explanation:
Is the following an element, compound, homogeneous mixture, or heterogeneous mixture?
Coca-cola
Answer:
CO2 is classified as a compound
Explanation:
3. Students were measuring distances and found one to be 2.04 m. When they asked the teacher if their measurement was correct, the teacher said, “Actually, it is 2.16 m.” What is the percent error?
Answer:
5.56
Explanation:
Helpppp
4. This group of substances tend to be malleable, ductile, and have relatively high melting points.
They are
(2 Points)
A.noble gases
B.nonmetals
C.metals
D.halogens
Answer:
The answer is metals
help me please im in 4th grade and online is frustrating
Answer:
A
Explanation:
The answer is A) because the A container has tightly packed molecules but not as tight as C so that means A is liquid, and C is a solid which makes B a gas
Answer:
The answer would be A
Explanation:
because in the first picture Liquid could be in many shapes like If I put water in my water bottle it would be the same shape as the water bottle.
In the third picture, the solid molecules will always be so close to each other like they will be stick to each other.
In the second picture, It will be separate always, as it cant stick to each other.
I hope I helped you!!!!
:)
Complete the sentence.
Atoms form chemical bonds to satisfy the
rule and to become
Answer:
Whats the sentence
Explanation:
Answer:
Atoms form chemical bonds to satisfy the octet rule and to become stable.
Got it right on Edg. 2020, hope this helps!
The metric unit of force is the Newton (N) , which is kg⋅m/s2 .
Convert 10 kg⋅cm/s2 to Newtons.
OPTIONS:
A. 1×10−1 N
B. 1×10−2 N
C. 1×10−5 N
D. 1×10−6 N
Answer:
1×10^-1 N
I took the quiz
Answer:
A
Explanation:
I just took the test.
How many fluorine atoms are present in 6.30 g of C2F4
Fluorine atoms = 1.517 x 10²³
Further explanationThe mole is the number of particles contained in a substance
1 mol = 6.02.10²³
Moles can also be determined from the amount of substance mass and its molar mass
[tex]\large{\boxed{\boxed{\bold{mol=\frac{mass}{molar\:mass}}}}[/tex]
Proust stated the Comparative Law that compounds are formed from elements with the same Mass Comparison so that the compound has a fixed composition of elements
Mass of F[tex]\tt mass~F=\dfrac{4.Ar~F}{MW~C_2F_4}\times mass~C_2F_4\\\\mass~F=\dfrac{4.19}{100}\times 6.3=4.788~gr[/tex]
mol of F[tex]\tt =\dfrac{4.788}{19}=0.252[/tex]
number of Fluorine atoms[tex]\tt 0.252\times 6.02\times 10^{23}=1.517\times 10^{23}[/tex]
Explain what intermolecular forces are, and how they are easily overcome.
Explanation:
Intermolecular forces are forces that exist between two or more molecules and they can be overcome at high temperatures.
Electron Dot Structures
Draw the electron dot structures for the following elements:
Magnesium (Mg)
Lithium (Li)
Argon (Ar)
Carbon (C)
Sulfur (S)
Helium (He)
Aluminum (Al)
Nitrogen (N)
Silicon (Si)
Hydrogen (H)
Calcium (Ca)
Neon (Ne)
Potassium (K)
Boron (B)
Chlorine (Cl)
Answer:
surf (S)
tide (T)
champion (C)
Explanation:
wag mo nlng pansinin
Which of the following occurs when a liquid becomes a gas
Answer:
Boiling occurs when a liquid changes to a gas below its surface as well as at the surface. The temperature at which a liquid boils is called its boiling point. The opposite of vaporization is called condensation. Sublimation occurs when the surface particles of a solid gain enough energy that they form a gas.Boiling occurs when a liquid changes to a gas below its surface as well as at the surface. The temperature at which a liquid boils is called its boiling point. The opposite of vaporization is called condensation. Sublimation occurs when the surface particles of a solid gain enough energy that they form a gas.Boiling occurs when a liquid changes to a gas below its surface as well as at the surface. The temperature at which a liquid boils is called its boiling point. The opposite of vaporization is called condensation. Sublimation occurs when the surface particles of a solid gain enough energy that they form a gas.Boiling occurs when a liquid changes to a gas below its surface as well as at the surface. The temperature at which a liquid boils is called its boiling point. The opposite of vaporization is called condensation. Sublimation occurs when the surface particles of a solid gain enough energy that they form a gas.
I need help with my chemistry homework
Speed in excess of 100 km/h, which is 208.8 km / h
Further explanationLinear motion consists of 2: constant velocity motion with constant velocity and uniformly accelerated motion with constant acceleration
• An equation of uniformly accelerated motion
[tex]\large {\boxed {\bold {x=xo+vo.t+\frac {1} {2} at ^ 2}}}[/tex]
vt = vo + at
vt² = vo² + 2a (x-xo)
x = distance on t
vo / vi = initial speed
vt / vf = speed on t / final speed
a = acceleration
I think it's not chemistry but physics
KnownΔx = 290 m
vf = 0⇒stop
Δt = 10 s
We use the formula in the question
[tex]\tt \Delta x=\dfrac{1}{2}(vf+vi)\Delta t\\\\290=\dfrac{1}{2}(0+vi).10\\\\vi=58~m/s=\boxed{\bold{208.8~km/h}}[/tex]
find the oxidation number of carbon in MgCO3
Answer: +2
Explanation: Formula of oxide is MgO, because oxidation state of Mg in MgCO3 is +2.
The amount of kinetic energy an object has depends on which feature of the object?
Answer:
mass
Explanation:
The amount of kinetic energy an object has, depends on its mass and its speed.
Answer: motion
Explanation:
I just took the quiz in edging
How do homes lose thermal energy?
I need TWO reasons on why we want to reduce the thermal loose.
Answer:
Poorly insulated attics, windows not being insulated in the winter
Explanation:
One reason is so we do not get cold in the winter and the reason we have a home is to protect us from the weather or put a shelter above us. Second reason is so we don't get hypothermia in the winter time.
if the gas has a volume of 20 L at a temperature of 25 Celsius what is the volume of the gas when it is heated to 100°C if the pressure remains constant
Answer:
i have no idea
Explanation:
lol
Answer:
this has to do with gas law
Explanation:
Charles law
v1=20
T1=25
V2=?
T2=100
hence V1/T1=V2/T2
V2=V1*T2/T1
V2=20*25/100
V2=5
Calculate the volume of a rock that has a mass of 24 g and a density of 8 g/mL
Answer:
24g÷8g/ml=3
volume =3
what is the mass of an atom if it has 11 protons, 12 neutrons, and 11 electrons
A,22, B.23, C34, D 11
Answer:
23, B
Explanation:
The mass of an atom is determined by the number of Protons + Neutrons. Here, if we assume the units is AMU (Which means the mass unit for a proton and neutron would be basically 1), the answer would be 11 + 12 = 23 AMU, which is B.
Answer:
B) 23
Explanation:
Relative Mass = number of protons + number of neutrons
Relative Mass = 11 + 12
Relative Mass = 23
1. An atom has 6 protons, 6 neutrons, and 6 electrons. What is the charge of the
atom's nucleus?
A.+6
B.+12
C.-6
D.-18
Answer:
+6
+6
+6
+6
+6
+6answer given
thanks
what is the density of an object with a mass of 100 grams and a volume of 50 cm
Answer:
2
Explanation:
because 100÷50=2m÷v=d
place the items in order from highest to lowest degree of internal organization.
tissue
organ system
organ
cell
Put them in order please PLEASE
Answer:
I hope this helps! Can I have Brainliest plz :)
Explanation:
Which of these processes are chemical reactions? Type the correct answer in each box.
Boiling an egg
Crushing spices
veges rotting
chopping veges
dew forming
I think colloids are
heterogeneous
because ____________
___________________
the particles do not dissolve completely..
What is an indicator? What does it tell you about solutions?
Answer:
Pure water is neutral, and so is petrol. An indicator is a substance that changes colour when it is added to acidic or alkaline solutions. You can prepare homemade indicators from red cabbage or beetroot juice - these will help you see if a solution is acidic or alkaline.
According to Bohr, why don't the electrons fly off into space?
Answer:
because Electrons are not little balls that can fly
Explanation:
A dark blue beaker labeled 100 millimeters Y has an arrow leading to a pale blue beaker labeled 99 millimeters H subscript 2 O. This has an arrow leading to a white beaker labeled 99 millimeters H subscript 2 O. Each arrow has a label 1 milliliter over it. The dark blue beaker has a box below it labeled Beaker number 1. The pale blue beaker has a box below it labeled Beaker number 2. The white beaker has a box below it labeled beaker number 3.
Does taking 1 mL of solution Y (pure bleach) out of the first beaker change the solution’s concentration?
What would the concentration of the second beaker be?
If Beaker #2 is a 1% solution of Y, and Beaker #3 is 1/100th of that in the final solution, what percentage solution would Beaker #3 be?
Answer:
3, 5, 1000
Explanation:
I took the test.
Answer:The first one would be 3
The second is 5
And the last one is 1000
Explanation:
6. What is one way a star with much more mass than the sun can end up?
white dwarf
red giant
neutron star
red dwarf
Answer:
neutron star
Explanation:
A massive star (More massive than the star) will undergo a supernova explosion. If the remnant of the explosion is 1.4 to about 3 times as massive as our Sun, it will become a neutron star. The core of a massive star that has more than roughly 3 times the mass of our Sun after the explosion will do something quite different