How and why was the periodic table set up?
PLS help!!!!!!!!
Why are halogen atoms never a central atom?
Answer:
They can’t have more than 8 valence electrons.
Explanation:
What's the molar mass of CoCl
Answer:129.839 g/mol
Explanation:
A chemical formula includes the symbols of the elements in the
compound and the subscripts that indicate*
how many atoms or ions of each type are combined in the simplest unit
the formula mass
the number of moles in each element
the charges of the elements or ions
Answer:
it indicates, how many atoms or ions of each type are combined in the simplest unit.
please help!!!!!!!!!!
Answer:
c
Explanation:
the other one doesn't make sense and when you read them with the sentence it kinda makes sense
why saturated fatty acid can’t create kink ?
Which are correct ???
Answer:
last one
Explanation:
endothermic reactions release energy
Which of the following increases with increasing atomic
number down a group?
Answer:
The number of energy levels increases as you move down a group as the number of electrons increases. Each subsequent energy level is further from the nucleus than the last. ... The outermost electrons are repelled by the inner shell electrons (Screening effect) and hence, the atomic size increases.
Explanation:Increase in atomic size
Will give brainliest, Look at the graph above. Compare it to the periodic table. What do you notice about the location on the periodic table of the elements that represent the high points
Answer:
We can see that the atomic radius decreases across every row.
Explanation:
I will comment more below.
The elements that represent the highest points on the graph are all elements of group 1 and occur at the head of the period to which they belong.
The periodic table is an arrangement of elements in groups and periods. The elements in the same group have the same number of valence electrons while the elements in the same period have the same number of shells.
Looking at the graph, we can see that the high points in the graph all correspond to the group 1 elements; sodium, potassium, rubidium and cesium.The have the highest atomic radii in the period. Atomic radii increases down the group but decreases across the period. Remember that these elements are at the head of the period to which they belong hence they have the highest atomic radii.
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Which of these solutions are basic at 25 °C ? A:[OH−]=2.53×10−7 M B:[H3O+]=9.99×10−9 M C:[H3O+]=6.31×10−4 M
Answer: frfg6
Explanation: 655tyyt
Write the symbol for every chemical element that has atomic number less than 73 and atomic mass greater than 173.2 u
C is the element symbol for which element?
a. Carbon
b. Cadmium
c. Celenium
d. Chlorine
Answer:
A) Carbon
Explanation:
the others are wrong its A
Answer:
A) carbon
Explanation:
carbon or simply c has an atomic number of 6 and it has an atomic mass of 12.01 amu. it belongs to group 4a
17. Which is a fat-soluble vitamin?
O vitamin B
O vitamin C
O vitamin A
please help 10 points asap
Answer:
opposite
Explanation:
Answer:
opposite
Explanation:
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The atom is one of the basic units of matter. Which part of the atom mostly determines the size of the atom?
a.Electrons
b.Nucleus
c.Neutrons
d.Protons
Answer:
Atomic size is the distance from the nucleus to the valence shell where the valence electrons are located. The separation that occurs because electrons have the same charge. The number of protons in the nucleus. The core electrons in an atom interfere with the attraction of the nucleus for the outermost electrons.
Explanation:
That would be B I believe, but please correct me if I'm wrong.
Which pattern on the periodic table is correctly predicted below?
Groups determine the number of valance electrons and periods determine the number of energy levels
Groups determine the number of energy levels and periods determine the number of valence electrons
Groups determine the number of protons, and periods determine energy levels
Groups determine the number of neutrons, and periods determine valence
Plzz
The process through which professional scientists evaluate the quality of each other’s research is called
group counsel.
group review.
peer counsel.
peer review.
Answer:
peer reveiw
Explanation:
Answer:
Peer review.
Explanation: Ask Edu
Whenever the same two elements form more than one
compound, the different masses of one element that combine
with the same mass of the other element are in the ratio of
small whole numbers.
TRUE
FALSE
Answer:
The answer is true
Explanation: Because The law of multiple proportions states that when two elements react to form more than one compound, a fixed mass of one element will react with masses of the other element in a ratio of small, whole numbers.
A rock rolls down a hill. Which form of energy is this an example of?
Chemical
Electrical
Mechanical
Thermal
Answer:
Mechanical
Explanation:
chemical
Explanation:
I took test 2020
How much heat would be required to convert 5.31 mol of a pure substance from a liquid at 40.0°C to a gas at 113.0°C?
Answer:
Q = 7.7 KJ
Explanation:
The complete question carries the following data:
Specific Heat Capacity of Liquid State = C(l) = 1.45 J/mol.°C
Specific Heat Capacity of Gaseous State = C(g) = 0.65 J/mol.°C
Boiling Temperature = Tb = 88.5°C
Heat of Vaporization = ΔH(vap) = 1.23 KJ/mol
Now, first we calculate the heat required (Q₁) to raise he temperature to boiling point:
Q₁ = n*C(l)*ΔT₁
where,
n = no. of moles = 5.31 mol
ΔT₁ = Temperature difference from 40°C to Tb = 88.5°C - 40°C = 48.5°C
Therefore,
Q₁ = (5.31 mol)(1.45 J/mol.°C)(48.5°C)
Q₁ = 373.4 J = 0.37 KJ
Now, we calculate the heat required (Q₂) to change its phase:
Q₂ = nΔH(vap)
Q₂ = (5.31 mol)(1.23 KJ/mol)
Q₂ = 6.53 KJ
Now, we calculate the heat required (Q₃) to raise he temperature to boiling point:
Q₃ = n*C(g)*ΔT₃
where,
n = no. of moles = 5.31 mol
ΔT₃ = Temperature difference from Tb to 113°C = 113°C - 88.5°C = 24.5°C
Therefore,
Q₃ = (5.31 mol)(0.65 J/mol.°C)(24.5°C)
Q₃ = 84.5 J = 0.08 KJ
So, the total heat required to convert 5.31 mol of this pure substance from a liquid at 40°C to a gas at 113°C is:
Q = Q₁ + Q₂ + Q₃
Q = 0.37 KJ + 6.53 KJ + 0.08 KJ
Q = 7.7 KJ
The total heat required to convert the pure substance from liquid to gas at the given temperature is 814 J.
The given parameters;
molar heat capacity of liquid, C(l) = 1.45 J/mol.⁰Cmolar heat capacity of gas, C(g) = 0.65 J/mol.⁰CThe total heat required to convert the pure substance from liquid to gas at the given temperature is calculated as follows;
[tex]Q = nc_l \Delta \theta + nc_g \Delta \theta \\\\ \Delta \theta = (113 - 40) = 73^0 C \\\\Q = (5.31 \ mol \times 1.45 \frac{J}{mol .\ ^0C} \times 73\ ^0C) + (5.31 \ mol \times 0.65 \frac{J}{mol .\ ^0C} \times 73 \ ^0C)\\\\Q = 814 \ J[/tex]
Thus, the total heat required to convert the pure substance from liquid to gas at the given temperature is 814 J.
"Your question is not complete, it seems to be missing the following information;"
How much heat would be required to convert 5.31 mol of a pure substance from a liquid at 40.0°C to a gas at 113.0°C? (molar heat capacity of liquid, C(l) is 1.45 J/mol.⁰C and molar heat capacity of gas, C(g) is 0.65 J/mol.⁰C).
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which body system carries oxygen, glucose and amino acids to all the cells of the body?
Answer:
Blood
Explanation:
This flows through the body so it gives it all over.
Which is located inside the lung?
Answer:what are the options????
Explanation:
Answer:
D. The Alveoli.
Explanation:
I need the answer multiple choice
Answer:
it's answer is
element of an atom ✌️
When given the following: density = 0.79 g/mL and mass =8g (answer can be found in your reading) What is the volume of the object?
HELP ASAP!!!!!!!!!!!!!
Answer:
V = 10.12 mL
Explanation:
Given that,
Density, d = 0.79 g/mL
Mass, m = 8 g
We need to find the volume of the object. Density is equal to the mass per unit volume. It can be given by :
[tex]d=\dfrac{m}{V}[/tex]
Where V is the volume of the object
[tex]V=\dfrac{m}{d}\\\\=\dfrac{8\ g}{0.79\ g/mL}\\\\V=10.12\ mL[/tex]
So, the volume of the object is 10.12 mL.
What mass in grams of MgSO4 is required to make 59.3 mL of 2.68 M
solution?
Answer:
Approximately [tex]19.1\; \rm g[/tex].
Explanation:
Number of moles of formula units of magnesium sulfate required to make the solutionThe unit of concentration in this question is "[tex]\rm M[/tex]". That's equivalent to "[tex]\rm mol \cdot L^{-1}[/tex]" (moles per liter.) In other words:
[tex]c(\mathrm{MgSO_4}) = 2.68\; \rm M = 2.68\; \rm mol \cdot L^{-1}[/tex].
However, the unit of the volume of this solution is in milliliters. Convert that unit to liters:
[tex]\displaystyle V = 59.3\; \rm mL = 59.3 \; \rm mL \times \frac{1\; \rm L}{1000\; \rm mL} = 0.0593\; \rm L[/tex].
Calculate the number of moles of [tex]\rm MgSO_4[/tex] formula units required to make this solution:
[tex]\begin{aligned}n(\rm MgSO_4) &= c \cdot V \\ &= 2.68 \; \rm mol \cdot L^{-1} \times 0.0593\; \rm L \approx 0.159\; \rm mol \end{aligned}[/tex].
Mass of magnesium sulfate in the solutionLook up the relative atomic mass data of [tex]\rm Mg[/tex], [tex]\rm S[/tex], and [tex]\rm O[/tex] on a modern periodic table:
[tex]\rm Mg[/tex]: [tex]24.305[/tex].[tex]\rm S[/tex]: [tex]\rm 32.06[/tex].[tex]\rm O[/tex]: [tex]15.999[/tex].Calculate the formula mass of [tex]\rm MgSO_4[/tex] using these values:
[tex]M(\mathrm{MgSO_4}) = 24.305 + 32.06 + 4 \times 15.999 \approx 120.361\; \rm g \cdot mol^{-1}[/tex].
Using this formula mass, calculate the mass of that (approximately) [tex]0.159\; \rm mol[/tex] of [tex]\rm MgSO_4[/tex] formula units:
[tex]\begin{aligned}m(\mathrm{MgSO_4}) &= n \cdot M \\&\approx 0.159 \; \rm mol \times 120.361 \; \rm g \cdot mol^{-1} \approx 19.1\; \rm g\end{aligned}[/tex].
Therefore, the mass of [tex]\rm MgSO_4[/tex] required to make this solution would be approximately [tex]19.1\; \rm g[/tex].
Which of the following elements has 3 electrons in the 2p sublevel?
O A. O
O B. C
O C. B
O DN
Answer:
the answer is D. N
AP3X
According to electronic configuration, there are 3 electrons in the 2p sublevel ,hence the correct option is D.
Electronic configuration is defined as the distribution of electrons that are present in an atom or molecule in an atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is important for understanding the structure of periodic table. It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions so as to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in their ground state and hence are said to be stable.
Thus, the correct option is D.
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How many grams of sodium hydroxide are present in a 250.0 ml of a 0.600M NaOH solution?
which type of rection has the general formuial ab+cd
what are the value and units for the speed of light
Answer:
299,792,458
Explanation:
PLEASE HELP !!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Which of the following does NOT increase with increasing temperature?
a kinetic energy
b thermal energy
c potential energy
d none of the above
Answer:
Explanation:
Potential energy