mendeleev's periodic table is studied even though it is considered to be defective
Answer:
This is because Mendeleev arranged the elements in order of increasing relative atomic mass.
Explanation:
Dmitri Mendeleev is one of the scientists that contributed to the development of periodic table in chemistry. He was able to organise elements into rows according to their atomic mass and into columns based on chemical and physical properties. This is the main reason why his periodic table is still studied even though it has some defects which include:
--> Grouping of elements that are not similar chemically: For example Copper and Silver bear no resemblance with the alkali metals, but they have been placed together in the first group.
--> Position of isotopes: According to his periodic table: Isotopes of an element must be given separate places in the periodic table because they have different atomic masses.
--> Electronic arrangement of elements: It failed to explain the electronic arrangement of elements.
--> Separation of chemically similar elements:
Elements that are chemically similar such as Gold and Platinum have been placed in separate groups.
What is the name of the compound with the formula B2C14?
Answer:
Diboron tetrachloride ---> B2Cl4
what is the atomicity of Sulphur?
Answer:
the atomicity of sulphur is 8
Explanation:
hope it helps
Help me please
The options are
A. Translation
B. Rotation
C. Enlargement
D.reduction
Answer:
C. Enlargement
Explanation:
Can someone help me with this question ASAP
A 2.50 L container is filled with 175 g of argon; a. If the pressure is 10 atm, what is the temperature ? b if the temperature is 22K, what is the pressure ?
Answer:
A. 70 K
B. 3.16 atm
Explanation:
We'll begin by calculating the number of mole in 175 g of Ar. This can be obtained as follow:
Mass of Ar = 175 g
Molar mass of Ar = 40 g/mol
Mole of Ar =?
Mole = mass / molar mass
Mole of Ar = 175 / 40
Mole of Ar = 4.375 moles
A. Determination of the temperature.
Mole of Ar (n) = 4.375 moles
Volume (V) = 2.50 L
Pressure (P) = 10 atm
Gas constant (R) = 0.0821 atm.L/Kmol
Temperature (T) =?
PV = nRT
10 × 2.5 = 4.375 × 0.0821 × T
25 = 4.375 × 0.0821 × T
Divide both side by (4.375 × 0.0821)
T = 25 / (4.375 × 0.0821)
T ≈ 70 K
B. Determination of the pressure.
Mole of Ar (n) = 4.375 moles
Volume (V) = 2.50 L
Temperature (T) = 22 K
Gas constant (R) = 0.0821 atm.L/Kmol
Pressure (P) =?
PV = nRT
P × 2.5 = 4.375 × 0.0821 × 22
Divide both side by 2.5
P = (4.375 × 0.0821 × 22) / 2.5
P = 3.16 atm.
Which of the following elements would have the largest electronegativity value?
O cesium
Olithium
O carbon
O sodium
Which of the following is an oxide which is strongly acidic?
(a) Na2O.
(b) MgO
(c) SiO2.
(d) P2O5.
Answer:
answer of your question is 4th
Explanation:
P205
Now look at the volcano map what type of boundary tends to give rise to volcanic activity
Answer:
Volcanoes occur primarily on convergent boundaries, specifically oceanic-continental convergent boundaries.
Explanation:
plato
How long does it take, on average, for one centimetre of soil to form
Rank these solutions from the most alkaline (1) to the least alkaline (5).
The acid dissociation constant, Ka, of HSO4- is 1.2 × 10-2. What does the Ka value indicate about this compound?
A.
HSO4- is a weak base.
B.
HSO4- is a strong acid.
C.
HSO4- is a weak acid.
D.
HSO4- is a strong base.
Answer:
The answer is HSO4- is a weak acid which will be C
The acid dissociation constant, ka, of HSO4- indicates that it is a strong acid. Details about acid dissociation constant can be found below.
What is acid dissociation constant?The acid dissociation constant denoted by Ka is the measure of the strength of an acid.
The dissociation constant of an acid is used to identify strong acids from their weak counterparts. Strong acids have high Ka values while weak acids have low Ka values.
According to this question, the Ka of HSO4- is 1.2 × 10-², which is quite high.
Therefore, the dissociation constant, ka, of HSO4- suggests that it is a strong acid.
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write electronic configuration of chlorine in its ionic state?
Answer:
1s2 2s2 2p6 3s2 3p6
Explanation:
Chlorine is a groups 17 element. The halogens for ions by accepting one electron to form univalent negative ions.
Since chlorine normally contains seventeen electrons, the chloride ion consists of eighteen electrons.
Hence the electronic configuration of chlorine ion is; 1s2 2s2 2p6 3s2 3p6.
please help me with this
Answer:
a. B
b. C
c. A
d. A
e. B
f. -266
g. B and D
Determine which elements or compounds are products in the
follow reaction equation:
Answer: D is the answer since it is the product of this equation
Explanation: HOPE I AM RIGHT AND IT HELPS!!!
need more explanation feel free to comment in the comment box
Which letter in the diagram represents the transition from liquid to gas?
A
B
C
D
Answer:
D
Explanation:
B is solid and liquid while D is liquid and gas
Answer:
Option ( D) is correct
The phase transition occurs at 100o C (the normal boiling point of water). Liquid water becomes water vapor or steam when it enters the gaseous phase.
Explanation:
A heating curve graphically represents the phase transitions that a substance undergoes as heat is added to it.
The liquid will begin to boil when enough heat has been absorbed by the solution that the temperature reaches the boiling point, where again, the temperature remains constant until all of the liquid has become gaseous water. At the atmospheric pressure of 1 atm, this phase transition occurs at 100o C (the normal boiling point of water). Liquid water becomes water vapor or steam when it enters the gaseous phase. Use the heat of vaporization ([latex]\Delta H_{vap}[/latex] ) to calculate how much heat was absorbed in this process: [latex]q=m\cdot C_{H_2O(g)}\cdot \Delta T[/latex], where m is the mass of the sample of water.
After all of the liquid has been converted to gas, the temperature will continue to increase as heat as added. Again, the heat added that results in a certain change temperature is given by: [latex]q=m\cdot C_{H_2O(g)}\cdot \Delta T[/latex] . Note that the specific heat capacity of gaseous water is different than that of ice or liquid water.
Is the graph more accurate with more atoms or less atoms?
Answer:
I would guess more atoms? but there is no graph attached
Pls help!!!
You are given a type of element by a teacher and she asks you to identify it.What should you do?Explain your answer
Answer:
NAO SRESONDEPORR PQUEOU BUOBRRRA IGAD THCAAUSEI
Explanation:
please help asap!!!!!!!!
The two waves in the diagram are occupying the same place at the same time. At what time will the interfering waves have an amplitude of zero? 1.0 3.0 4.0 7.0 Mark this and return
Answer: It’s 4.0
Explanation: I just took the test and got it right:)
Draw the structure for :
3,3,4-trimethylhex-2-ene
Answer:
answer is in the picture.
balance the equation .......qn 5.......help
Answer:
MnO4 + 4 H2C2O4 = Mn + 8 CO2 + 4 H2O
H2S04+CaCO3—>Ca S04+H20 +CO 2
help me balance it
Answer:
It's already balanced.
Explanation:
REACTANTS PRODUCTS
H = 2 H =2
S = 1 S = 1
O = 7 O = 7
Ca = 1 Ca = 1
C = 1 C =1
ii.
ci
What is the name of the organic compound
Answer.
Hydrocarbons are compounds that contain carbon and hydrogen only
Explanation:
a. c3H4 methane
b.c3H4.propene
c.c5H8
phosphorus react with carbon
Answer:
Phosphorus atoms can bond with oxygen atoms to form ester groups. These can bond with carbon atoms, yielding a large number of organic phosphorus chemicals. These are found in many important biological processes
A gas has an initial volume of 52.3 L at 273 Kelvin. What is its temperature when the volume reaches 145.7 L?
Answer:
[tex]\boxed {\boxed {\sf 761 \ K}}[/tex]
Explanation:
We are asked to find the new temperature of a gas after a change in volume. We will use Charles's Law, which states the volume of a gas is directly proportional to the temperature. The formula for this law is:
[tex]\frac {V_1}{T_1}= \frac{V_2}{T_2}[/tex]
The volume is initially 52.3 liters at a temperature of 273 Kelvin.
[tex]\frac {52.3 \ L}{273 \ K}= \frac{V_2}{T_2}[/tex]
The volume reaches 145.7 liters at an unknown temperature.
[tex]\frac {52.3 \ L}{273 \ K}= \frac{145.7 \ L }{T_2}[/tex]
We are solving for the new temperature, so we must isolate the variable T₂. Cross multiply. Multiply the first numerator and second denominator, then the first denominator and second numerator.
[tex]52.3 \ L * T_2 = 273 \ K * 145.7 \ L[/tex]
Now the variable is being multiplied by 52.3 liters. The inverse of multiplication is division. Divide both sides by 52.3 L.
[tex]\frac {52.3 \ L * T_2 }{52.3 \ L}=\frac{ 273 \ K * 145.7 \ L}{52.3 \ L}[/tex]
[tex]T_2=\frac{ 273 \ K * 145.7 \ L}{52.3 \ L}[/tex]
The units of liters cancel.
[tex]T_2=\frac{ 273 \ K * 145.7 }{52.3 }[/tex]
[tex]T_2 = 760.5372849 \ K[/tex]
The original measurements have at least 3 significant figures, so our answer must have 3. For the number we found, that is the ones place. The 5 in the tenths place tells us to round the 0 up to a 1.
[tex]T_2 \approx 761 \ K[/tex]
When the volume reaches 145.7 liters, the temperature is 761 Kelvin.
Can someone help with this
Answer:
I think option (d) is right answer
Answer:
I think that the answer is option(C)
Had beryllium and calcium already been discovered
Answer:
Yes
Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. ... Notable gemstones high in beryllium include beryl (aquamarine, emerald) and chrysoberyl.
Calcium is a mineral that is necessary for life. In addition to building bones and keeping them healthy, calcium enables our blood to clot, our muscles to contract, and our heart to beat. About 99% of the calcium in our bodies is in our bones and teeth.
¿Que es bacteria y un virus ?
es para hoy por favor ayúdeme
i) Las bacterias son organismos microscópicos unicelulares que prosperan en diversos entornos. Estos organismos pueden vivir en el suelo, el océano y dentro del intestino humano.
ii) Un virus es un agente infeccioso submicroscópico que se replica solo dentro de las células vivas de un organismo. Los virus infectan todas las formas de vida, desde animales y plantas hasta microorganismos, incluidas bacterias y arqueas.
Explain the steps you would follow to make 500 mL of a 0.3 M solution of sucrose
(C12H22011) in the lab.
Answer:
see explanation
Explanation:
Solutions are prepared from one of three solute sources ...
- solid solute from manufacturer,
-liquid solute from manufacturer,
-stock concentrate of solute for dilution to lower concentrations.
In this problem, sucrose is a stock solid with a formula mass of 342.3 grams/mol. The amount of solid needed can be determined using the formula:
mass of solute needed (grams) = (Molarity needed x Volume needed in Liters x formula weight) / (decimal fraction purity of stock solid)
Molarity needed = 0.3M
Volume needed = 500 ml = 0.500 liters
Formula weight = 342.3 grams/mole
Purity factor (assumed) = 100% = 1.00 (should be posted on stock bottle label) For example, a 95% pure stock solid => purity factor of 0.95.
∴ grams of sucrose needed = (0.3M*)(0.500L)(342.3g/mole)/(1.00) =51.345 grams sucrose.
Measure 51.345 grams of sucrose into mixing vessel and add solvent water up to, but not to exceed 500 ml total volume. Mix until homogeneous.
What is an air mass? Where on Earth might you find a hot and dry air mass?
An air mass is a volume of air whose temperature and humidity are specified. Many hundreds or thousands of square miles are covered by air masses, which adjust to the properties of the land underneath them.
What is an air mass ?An air mass is a volume of air whose temperature and humidity are specified. Many hundreds or thousands of square miles are covered by air masses, which adjust to the properties of the land underneath them. Latitude and their continental or marine source regions are used to categorize them.
There is a temperature and air pressure differential. Storms are caused by abrupt changes in the weather. Two natural wind patterns come into conflict.
The hot and dry continental tropical (cT) air mass is prevalent over subtropical and tropical continents. The world's largest deserts, such the Sahara, Arabian, and Australian, are important source areas.
Thus, Latitude and their continental or marine source regions are used to categorize them. An air mass is a volume of air whose temperature and humidity are specified.
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