Answer:
Because they have complete electronic configuration
Explanation:
Group 18 elements are known as the noble or inert gases. The elements in this group are non-reactive because they have complete electronic shell configuration.
Electronegativity is the tendency of an atom to attract electrons. The reason why atoms attracts electrons is to have a stable configuration like those of the noble gases. Since the noble gases do not require any extra-electrons to attain stability, they have 0 electronegative values.Where do convection currents occur?
A.
In areas with the same temperature
B.
In areas with different air pressures
C.
In areas with the same altitude
D.
In areas with different cloud types
Answer:
a because where the air travels for example a radiator
Answer:
C.
In areas with the same altitude
Explanation:
Imagine you're cooking dinner for a few of your friends. You decide to make a salad with homemade dressing. Why do you need to think about the polarity of the different ingredients in your salad dressing in order for it to turn out well? Answer in 1 to 2 paragraphs. (10 points) Think about how polar molecules only mix with other polar molecules and nonpolar molecules only mix with other nonpolar molecules.
Answer:15
Explanation:
A_________is the distance from one compression to the next compression in a longitudinal wave. (Page 2 Vocabulary)
A.frequency
B.rarefaction
C.amplification
D.wavelength
Answer:
wavelength
Explanation:
Suggest whether water freezing is an endothermic or exothermic process. Can you explain your suggestion?
Question 12 of 25
Which sentence describes all atoms of one element?
O A. They have the same number of protons.
OB. They have the same number of neutrons.
O C. They have the same number of isotopes.
D. They have the same properties.
Answer:
D They have the same properties.
Explanation:
The same no. of isotopes doesnot describes because isotopes have same symbol but didderent atomic mass.
Fill in the coefficients that will balance the following reaction:
PbI4 +
CrCl3 →
PbCl4 +
CrI3
the equation balanced is
3 PbI4 + 4 CrCl3 → 3 PbCl4 + 4 CrI3
Answer:
3,4,3,4
Thank me later!
Explanation:
(10 POINTS PLS ANSWER IF U KNOW)
Is the coloring of the peppered moths an example of competition, differential reproductive success, or inherited variation? Explain why.
Answer:
Competition
Explanation:
Peppered moths get their color in lieu to become the fittest among all so that they can survive easily. During industrial age, when pollution suddenly became high these moths changed their color through evolution in order to save themselves from their predators.
PLS GIVE BRAINLIEST
Please help this is chemistry.
Answer:
C
Explanation:
the rest are trends except for Electronegativity
What is the net force on a car stopped at a stop sign?
Help please! Tell me which one goes where.
Answer:
human-F
chicken-D
rabbit-E
tortoise-C
salamander-B
fish-A
Explanation:
hope this helped!!
I tried my best!!
please mark me as brainliest
HAVE A GREAT DAY <3
Answer:
D Tortoise
B Salamander
A Fish
C Chicken
F Human
E Rabbits
Explanation:
I Really have an Explanation
An exacuted glass vessel weighs 50 g when empty, 148g when filled with an liquid of density o.989/cc and 50.5 g whenfilled with an ideal gas760 mmHg and at 300k. Determine the molecular weights of gss.
MW of gas : 124.12 g/mol
Further explanationDensity is a quantity derived from the mass and volume
Density is the ratio of mass per unit volume
With the same mass, the volume of objects that have a high density will be smaller than objects with a smaller type of density
The unit of density can be expressed in g/cm³ or kg/m³
Density formula:
[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]
ρ = density
m = mass
v = volume
glass vessel wieight = 50 g
glass vessel + liquid = 148 ⇒ liquid = 148 - 50 =98 g
volume of glass vessel :
[tex]\tt V=\dfrac{m}{\rho}=\dfrac{98}{0.989}=99.1~ml[/tex]
An ideal gas :
m = 50.5 - 50 = 0.5 g
P = 760 mmHg = 1 atm
T = 300 K
[tex]\tt PV=\dfrac{mass(m)}{MW}.RT\\\\MW=\dfrac{m.RT}{PV}\\\\Mw=\dfrac{0.5\times 0.082\times 300}{1\times 0.0991}=124.12~g/mol[/tex]
An atom with which atomic diagram is most similar to calcium?
Answer:
C
Explanation:
Calcium is an element with a total of 20 electrons.
It has 4 shells with a configuration of:
2, 8, 8, 2
Option C is the most similar to calcium but the number of shells is not complete.
It still requires two more shells with 8 and two electrons respectively.
The Bohr model of the atom suggest that the protons and neutrons are found in the nucleus and the electrons orbit the nucleus much line planets around the sun. How is our modern model of the atom different from this model?
Answer:
D) The electrons move around the nucleus in an electron cloud
Explanation:
i just did it on usa test prep !
Carl makes the table below to determine the number of atoms of each element in the chemical formula 4Ca(ClO3)2.
A table with 3 columns and 2 rows. The first column labeled element has entries calcium, chlorine, oxygen. The second column labeled calculation has entries 1 times 4 , 1 times 2, 3 times 2. The third column labeled total atoms has entries 4, 2, 6.
What mistake did Carl make?
Answer:
calcium chloride oxide
Answer:
He did not multiply the chlorine and oxygen atoms by the coefficient 4
Explanation:
I just took the quiz
An example of a decomposer is a:
rabbit
mushroom
tulip
Answer:
mushroom
Explanation:
Which of the following is not likely to occur if a city loses its tax base due to economic decline? A. The city will have fewer police and fire fighters. B. City residents will have adequate health care and hospital services. C. The city will have a decline in public housing. D. Public and private buildings will decay.
Answer:
B.
City residents will have adequate health care and hospital services.
Explanation:
the correct answer for edg 2020
Answer:
B
Explanation:
Atoms and ions are all the same.
Answer:
Yes they are
Explanation:
A unit of substance that contains the Avogadro number of atoms or molecules is referred to as a ____________ of the substance.
Answer:
A unit of substance that contains the Avogadro number of atoms or molecules is referred to as a mole of the substance.
Explanation:
The mole (symbol: mol) is the unit of measurement for amount of substance in the International System of Units (SI). A mole of a substance or a mole of particles is defined as exactly 6.02214076×1023 particles, which may be atoms, molecules, ions, or electrons. In short, for particles, 1 mol = 6.02214076×1023.
The first atomic structure *
Yes
NO
Answer:
Yes? Sry I’m kinda confused
Explanation:
Sry if I’m wrong
A 100g of sample of a compound is combusted in excess oxygen and the products are 2.492g of CO2 and 0.6495 of H2O. Determine the empirical formula of the compound?
The empirical formula : C₁₁O₁₄O₃
Further explanationThe assumption of the compound consists of C, H, and O
mass of C in CO₂ =
[tex]\tt \dfrac{12}{44}\times 2.492=0.680~g[/tex]
mass of H in H₂O =
[tex]\tt \dfrac{2.1}{18}\times 0.6495=0.072~g[/tex]
mass of O :
mass sample-(mass C + mass H)
[tex]\tt 1-(0.68+0.072)=0.248`g[/tex]
mol of C :
[tex]\tt \dfrac{0.68}{12}=0.056[/tex]
mol of H :
[tex]\tt \dfrac{0.072}{1}=0.072[/tex]
mol of O :
[tex]\tt \dfrac{0.248}{16}=0.0155[/tex]
divide by 0.0155(the lowest ratio)
C : H : O ⇒
[tex]\tt \dfrac{0.056}{0.0155}\div \dfrac{0.072}{0.0155}\div \dfrac{0.0155}{0.0155}=3.6\div 4.6\div 1\\\\\dfrac{11}{3}\div \dfrac{14}{3}\div \dfrac{3}{3}=11:14:3[/tex]
If 30cm³ of 0.45 mol dm3 HCl reacted with NaOH, how many moles of HCl reacted?
Moles HCl reacted : 0.0135
Further explanationMolarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution
[tex]\large {\boxed {\bold {M ~ = ~ \dfrac {n} {V}}}[/tex]
Where
M = Molarity
n = Number of moles of solute
V = Volume of solution
So to find the number of moles can be expressed as
n = V x M
The volume of HCl 30 cm³=3.10⁻² dm³
Molarity of HCl = 0.45 mol/dm³
so moles HCl reacted :
[tex]\tt n=3.10^{-2}\times 0.45=0.0135[/tex]
For this reaction, C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O, the ∆H is –2200 kJ. If two moles of C3H8(g) reacted with excess oxygen, what would be true?
A) 4400 kj of heat released into surroundings
B) 4400 kj of heat absorbed by system
C) 1100 kJ heat released into surroundings
D) 1100 kJ heat absorbed by system
A) 4400 kj of heat released into surroundings
Further explanationReaction
C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O, the ∆H is –2200 kJ
Reaction exothermic( ∆H=-, released heat to surrounding) and for combustion of 1 mole of C3H8
So for two moles of C3H8, the enthalpy :
[tex]\tt -2200\times 2=-4400~kJ[/tex]
What is the specific heat of a substance that absorbs 2500 joules of heat when a sample of 100g of the substance increases in temperature from 10.°C to 70.°
Answer:
0.417 J/gºC
Explanation:
From the question given above, the following data were obtained:
Heat (Q) absorbed = 2500 J
Mass (M) of substance = 100 g
Initial temperature (T1) = 10 °C
Final temperature (T2) = 70 °C
Specific heat capacity (C) =?
Next, we shall determine the change in temperature (ΔT). This can be obtained as follow:
Initial temperature (T1) = 10 °C
Final temperature (T2) = 70 °C
Change in temperature (ΔT) =?
Change in temperature (ΔT) = T2 – T1
Change in temperature (ΔT) = 70 – 10
Change in temperature (ΔT) = 60 °C
Finally, we shall determine the specific heat capacity of the substance as follow:
Heat (Q) absorbed = 2500 J
Mass (M) of substance = 100 g
Change in temperature (ΔT) = 60 °C
Specific heat capacity (C) =?
Q = MCΔT
2500 = 100 × C × 60
2500 = 6000 × C
Divide both side by 6000
C = 2500 / 6000
C = 0.417 J/gºC
Therefore, the specific heat capacity of substance is 0.417 J/gºC
when molecules move they react by cooling down.
True or False?
Answer:
false
Explanation:
when molecules move they heat up
Which of the following is not a subatomic particle?
O Electron
O Neutron
O Nucleus
O Proton
The nucleus is not a subatomic particle, but rather made of the subatomic particles of protons and neutrons. An electron is also a subatomic particle, but it is not found in the nucleus. There are many other subatomic particles, but your teacher probably won't go over those terms until later.
How many atoms of each element are in one molecule of 2-heptanone
Answer:
A chemical structure of a molecule includes the arrangement of atoms and the chemical bonds that hold the atoms together. The 2-HEPTANONE molecule contains a total of 21 bond(s) There are 7 non-H bond(s), 1 multiple bond(s), 4 rotatable bond(s), 1 double bond(s) and 1 ketone(s) (aliphatic).
Answer:
Explanation:
CH3 provides 1 Carbon
C4 provides 4 carbons
COC provides 2 more
Total 7 Carbons
======================
COCH3 Provides 1 Oxygen
======================
CH3 provides 3 Hydrogens
C4H8 provides 8 hydrogens
COCH3 has 3 more hydrogens
Total 14 hydrogens
The answer should be B.
You should note that there are no brackets which means you only need to read the small numbers going down behind each element. You might have to read that sentence a could of times, but it is important to know.
Describe two physical properties of matter and how those properties are measured.
Help plzzzz urgent !!!!!!!!!!!!!!
Answer: B < C < A
Explanation:
Ok so things that have the lowest pka are the strongest acids. the higher the pka the less acidic it is.
how is oxidation of copper seen on the statue of liberty similar to flammability and how is it different from flammability?
Answer:
Flammability and oxidation of copper are both chemical properties of a substance.Chemical properties are the properties that tells us how a substance can react with others.Flammability, oxidation of copper, rusting of iron, precipitation e.t.c are chemical properties of a substance.Flammability is one important chemical property of hydrocarbons.Oxidation reaction is peculiar to copper.
Explanation:
The _____________ is similar to a vacumn cleaner because it cleans up cell waste.
a
endoplasmic reticulum
b
lysosome
c
mitochondria
d
cell wall