Answer:
Mendeleev’s periodic table is, based on the relation of elements’ properties as dependent on the atomic weight of the element. But the Modern periodic table considers atomic number as the fundamental property that decides the properties of elements.
The modern periodic table does correct the defects of Mendeleev’s periodic table. For example, in Mendeleev’s periodic table, in the element pairs, Argon-potassium, cobalt-nickel, tellurium-iodine and thorium and protactinium, elements with higher atomic mass precede the element with lower atomic weight. However, it is the right places for them but is against Mendeleev’s periodic law.
These elements atomic number shows the reverse order compared to atomic mass. The supposed to be wrong positions in Mendeleev’s table has the right explanation justifying their positions.
a radioactive element has a half-life of 30 days. calculate the mass of the element that remains after 20 days if 100g of the element decays. Also, calculate the decay constant.
Answer:
A=Ao(1/2)^t/h
A=(100)(1/2)^20/30
A=63g
4. Complete the reaction : Copper Sulphate (Cuso.) + Iron (Fe)-> + Copper ( Cu) ,1. Zinc Sulphate ( ZnSO2) ,
2.Magnesium Sulphate (MgSO) 3. Ferrous Sulphate ( FeSOA),4. None of these
Copper Sulphate (CuSO₄) + Iron (Fe) → __Ferrous Sulphate ( FeSO₂)__ + Copper ( Cu)
Since we know the reactants and one of the products, we can work backward to discover what the other reactant may be.
As it is in the question, we can map the reactants and product:
Reactants Product
Copper Copper
Sulphate _____
Iron _____
This indicates that the product is a combination of Iron and Sulphate. Since Sulphate is of Valency two and Iron would want to match this valency, the likely product is Iron (II) Sulphate, commonly known as Ferrous Sulphate.
A hot chunk of metal at 120 degrees Celsius is put into water at 20 degrees Celsius.
What will happen to the temperatures of the materials?
A. metal and water will both end up at 140 °C
B. metal and water will both end up at 60 °C
C. metal temperature will decrease to 20 °C
D. water temperature will increase to 120 °C
i believe the answer is B: both wind up at 60°C
but it's also reasonable to assume, given enough time, they wind up at 20°C because the water would heat up to cool the metal then slowly release the heat to the air untill they both reach 20°C
if it were me I'd answer B, apologies if I'm wrong
Balancing oxidation-reduction reactions
Mg+ N2—>Mg3N2
Answer:
[tex]{ \sf{3Mg_{(s)} + N_{2(g)} →Mg _{3}N_{2(s)}}}[/tex]
a current of 1.5 a is flowing through a 4 resistor.
Answer:
than what can i do lol
If you mix sand and water in a container the sand will sink to the bottom. explain why
Answer:
Sand is heavier than water and cannot float in water, so it will sink to the bottom.
equal volumes, 50.0 ml of 0.54897 M solution of HCl and 0.9573 M NaOH solutions having an initial temperature of 18.5 degree Celsius react in a coffee cup calorimeter. The resultant solution records a temperature of 22.9 degree Celsius. since the solutions are mostly water, the solutions are assumed to have a density of 1.0g/ml and a specific heat of 4.184 j/g degree Celsius. The heat capacity of the calorimeter is 1.0*10^1 j/degree Celsius.
a) calculate the heat gained or released by the solution at a constant pressure in j.
b)calculate the q reaction in kj
c) which reagent is limiting
D) calculate delta Hrxn (kj/mol)
Answer:
a) calculate the heat gained or released by the solution at a constant pressure in j.
Carbonic acid weathering limestone
a
Chemical Change
b
Physical Change
How many kilojoules are required to raise the temperature of a 150. g sample of silver from 25 °C to 135 °C? Silver has a specific heat of 0.235 J/g °C.
Answer:
3.8775 kJ
Explanation:
The formula is Q=mcdeltat
We know m (mass) is 150, c (specific heat) is 0.235, and delta t (change in temperature) is 135-25=110
Plug that in and solve for Q
150*0.235*110=3877.5 J
The problem is that this is still in joules so we have to convert to kilojoules
3877.5 J * 1 kJ/1000 J = 3.8775 kJ
Cordell bought new tires for his bicycle. As he rode his bike on the hot street, the temperature of the air in the tires increased. If the volume of the air stayed the same, what happened to the pressure inside the tires?
Answer:
the pressure increased
Could someone plz help me? Giving brainliest
Answer:
its D
Explanation:
A and C are ruled out because an opnion of scientist doesnt make the a law and B is not always true
Nitrogen oxide emissions combine with water vapor, producing nitric acid
a
Chemical Change
b
Physical Change
Answer:
chemical change
I hope it's helps you
The number of bonds in nitrogen molecule is:
Answer:
3 is the answer.
Explanation:
Nitrogen atoms will form three covalent bonds (also called triple covalent) between two atoms of nitrogen because each nitrogen atom needs three electrons to fill its outermost shell.
Answer:
3
Explanation:
If particles of a solid move slow and particles of
a gas move fast, which would have higher
kinetic energy (KE)?
Answer:
The gas particles would have higher Kinetic energy.
Explanation:
From the formular of kinetic energy:
[tex]{ \sf{KE = \frac{1}{2}m {v}^{2} }}[/tex]
KE is the kinetic energy possessed by particle.
KE is the kinetic energy possessed by particle.m is the particle mass.
KE is the kinetic energy possessed by particle.m is the particle mass.v is the velocity attained by a particle
[tex]{ \sf{KE = \{ \frac{1}{2} m \}} {v}^{2} }[/tex]
keeping the mass, m constant:
[tex]{ \sf{KE = k {v}^{2} }}[/tex]
Therefore, KE is directly proportional to v² :
[tex]{ \sf{KE \: \alpha \: {v}^{2} }}[/tex]
so, when velocity increases, KE also increases.
Which of following affects liquifaction of gases except
(2 Points)
Melting point
Volume
Temperature
Pressure
Answer:
pressure
Explanation:
gas convert to liquid at high pressure.
GIVING 20 POINTS // SEP Analyze Data - The properties of matter can be classified into two groups. Extensive properties vary with the amount of matter in a sample. Intensive properties remain the same, or are independent of the amount of matter present. Analyze the data in the table to identify examples of extensive and intensive properties. Explain your classifications.
Answer:
Intensive Properties: Appearance, State, Reactivity, Density
Extensive Properties: Mass, Volume
Explanation:
Intensive Properties: Appearance, State, Reactivity, and Density values all stay the same, regardless of the amount of material.
Extensive Properties: Mass, and Volume depend on the amount of material present
Mass and volume are extensive properties.
Physical state, densities, appearances, and reactivities are intensive properties.
Explanation:
Extensive properties are those properties that depend upon the mass of the matter of substance. Cannot be used to identify the substance Intensive properties are those properties that do not depend upon the mass of the matter of substance. Can be used to identify the substanceIn the table given, we can see:
The mass and volume of even the same elements are differing this is because the amount of matter present in them is different.Mass and volume are extensive properties.
The physical state, densities, appearances, and reactivities of the respective elements are very much similar to their kind which means that these properties are not dependent on the size or volume of the elements.The physical state, densities, appearances, and reactivities are intensive properties.
Learn more about properties of the matter here:
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ANSWER QUICK PLEASE!!!! 25 POINTS
Acrylonitrile and ethyl acetate have the same boiling point: 77.2ºC. In one to two sentences, explain what outcome you would expect if a mixture of these two substances were distilled.
The two substances can never be separated by distillation because distillation depends on difference in boiling point.
Distillation is a separation method that depends on difference in boiling point between two substances.
Usually, the substance having a lower boiling point is collected first as the temperature is gradually raised. The substance having a higher boiling point then follows.
However, since the two substances have the same boiling point, they can not be separated by distillation because they will be converted to vapor simultaneously thereby making separation impossible.
Learn more: https://brainly.com/question/15946045
A school bus travels 40 kilometers in 1 hour. What is the appropriate unit for the average speed of the school bus?
Answer:
The average speed is = 11.1m/s
Explanation:
Recall that average speed is defined as the total distance traveled with respect to the total number of time, therefore we say that the total distance traveled is 40Km according to your question, remember, the unit of speed is metre per second, so you change 40km by multiplying it with 1000, recall that, 1000m = 1km, so 40km×1000m = 40,000m, also 1h= 60×60, =3600s
Remember the formula for average speed is = Total distance traveled÷ total time taken
Thus; 40000m/3600s
Then we had, 11.1m/s...
You can ask questions
What is the density of an object that has a mass of 5.8g and a volume of 2.1 mL?
Answer:
[tex]\boxed {\boxed {\sf 2.8 \ g/mL}}[/tex]
Explanation:
Density is an object's mass per unit volume. The formula for calculating density is:
[tex]\rho= \frac{m}{v}[/tex]
The mass of the object is 5.8 grams and the volume is 2.1 milliliters.
m= 5.8 g v= 2.1 mLSubstitute the variables into the formula.
[tex]\rho = \frac{5.8 \ g}{2.1 \ mL}[/tex]
Divide.
[tex]\rho = 2.761904762 \ g/mL[/tex]
The original values of mass and volume (5.8 and 2.1) have 2 significant figures, so our answer must have the same. For the number we calculated, that is the tenths place. The 6 in the hundredth place tells us to round the 7 in the tenth place up to an 8.
[tex]\rho \approx 2.8 \ g/mL[/tex]
The density of the object is approximately 2.8 grams per milliliter.
what is combination reaction give two examples
Which variable do you change during an experiment? This is often associated with the IF part of the hypothesis.
Constant Variable
Control Variable
Independent Variable
Dependent Variable
d
Answer:
Independant variable
Explanation:
Say you were doing a lab, you wanted to know if fertilizer actually helped a plant grow. The growth of a plant, in this situation, depends on whether you use fertilizer or not. You are changing if you use it or not, so it is the independent variable.
Would you categorize temperature as an Intensive or extensive property explain plz !!!
Extensive properties depend on the amount of matter in a sample, While Intensive properties do not depend on the amount of matter in a substance.
~this table resembles a condensed version of the modern periodic table. using the full periodic table as a reference, type the symbols for the elements from part A into this table based on their appropriate group and period.
Explanation:
H, He ---------
Li, Be, --,C, F, Ne
Na, Mg, --,Si, Cl, Ar
K, Ca, Cu, Ge, Br, Kr
Rb, Sr, Ag, Sn, I, Xe
Cs, Ba, Au, Pb, At, Rn
Please give brainliest, I spent a lot of effort on this.
An ice wedge shattering a slab of shale
a
Chemical Change
b
Physical Change
Answer:
Physical Change
Explanation:
Its a physical change because it is not changing its molecular structure it is only changing the shape of the shale.
I don't know what to do...
from my thinking. you should find a solid..then try finding its volume.
Cuales son los elementos (de la tabla periodica) que contienen los seres inertes (minerales)
Osea por ejemplo las piedras, el agua, la tierra, cuales son los elementos del universo que conforman cosas no-vivas?
How is the atomic mass of an element determined?
A. by adding the masses of the protons and electrons
B. by adding the masses of the neutrons and electrons
C. by determining the number of protons
D. by adding the masses of the protons, neutrons, and electrons
Answer:
D
Explanation:
Atomic mass is the total mass of protons, neutrons and electrons of an atom at rest
EASY 30 POINTS! PLS HELP ME T-T
1. True or false? All atoms in an element contain an identical number of neutrons.
2. An atom with a _______ charge has the same number of protons and electrons.
3. An atom that has a different number of electrons and protons is called a(n) _______.
Answer:
1.false
2.neutron
3.neutron
Answer:
1. false
2. zero
3. isotopes
hope it helps
what is the density of a rock that has a volume of 56 ml and a mass of 170 g?
Answer: The density of the rock is 3.03
Explanation:
Density formula:
P = mass/volume
= 170/56
= 3.03
Note: cannot measure density, so there is no sign beside it.
A student reacts 3.0 g of magnesium with 2.5 mol / dm3 sulfuric acid.Calculate the minimum volume of sulfuric acid that reacts with all the magnesium
3.og idbj mass of mjemantg 2.oml