Answer:
Noble Gases B
Explanation:
The noble gases are the chemical elements in group 18 of the periodic table. They are the most stable due to having the maximum number of valence electrons their outer shell can hold. Therefore, they rarely react with other elements since they are already stable.
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.
Suggest whether water freezing is an endothermic or exothermic process. Can you explain your suggestion?
The first atomic structure *
Yes
NO
Answer:
Yes? Sry I’m kinda confused
Explanation:
Sry if I’m wrong
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.
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]
Match the term with the definition.
Condensation
Evaporation
Sublimation
Freezing
A) A phase change from a gas to a liquid
B) A phase change from a solid to a gas
C) A phase change from a liquid to a gas
D) A phase change from a liquid to a solid
[Please Hellp!]
Which atom in the following sets has the larger atomic radius?
a. Rn, Ne, Ar, Kr
b. Hg, Cs, Po, W
c. Mg, P, Al, Ar
Answer:
A.Rn,Ne,Ar,Kr.......
when molecules move they react by cooling down.
True or False?
Answer:
false
Explanation:
when molecules move they heat up
The breaking and forming of bonds between atoms in substances results in changes in the _______ contained in the substances.
Answer:
Electrons
Explanation:
The breaking and forming of bonds between atoms in substances results in changes in the number of electrons in the substance.
Atoms combined in order to share, gain or lose electrons for it to be stable. The noble gases have a set up configuration which makes them stable. All atom tend to mimic the noble gases.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.
how can air produce a pressure
IN OWN WORDS NOT FROM GOOGLE
Answer:
Gas pressure is caused when gas particles hit the wall of their contains. the more often the particles hit the walls, and the faster they are moving when they do this , the higher the pressure .
Explanation:
Describe two physical properties of matter and how those properties are measured.
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]
Which of the following laboratory procedures best illustrates the law of conservation of mass? (Assume the product of the reaction includes the mass of any unused reactants.) (3 points)
Reacting 12 g of C with 32 g of O2 to form 44 g of CO2
Weighing 100 g of Cu powder and 100 g of Fe filings
Heating 100 g of CaCO3 to produce 56 g of CaO
Dissolving 10 g of NaCl in 100 g of water
Answer: Reacting 12 g of C with 32 g of O2 to form 44 g of CO2
Explanation: I took the test just now, and the law of conservation of mass means to energy and that is exactly what they do in this answer!
Answer:
A
Explanation:
The _____________ is similar to a vacumn cleaner because it cleans up cell waste.
a
endoplasmic reticulum
b
lysosome
c
mitochondria
d
cell wall
How many moles of
C
O
2
COX
2
will be produced from
97.0
g
97.0 g97, point, 0, start text, space, g, end text of
C
3
H
8
CX
3
HX
8
, assuming
O
2
OX
2
is available in excess?
Answer:
Im highy
Explanation:
Which of the following are soluble in water: salt, gravel, or pepper
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.
PLEASE HELP!!!!! NEED HELP ASAP!!!!!
Write the chemical formula for the ionic compounds below
EXAMPLE- Calcium Phosphide= Ca3P2
Magnesium chloride=
Aluminum Fluoride=
Lithium Bromide=
Potassium Sulfide=
Answer:
down below
Explanation:
MgCl2
AlF3
LiBr
K2S
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.
Sea-Floor Spreading1. The arrows on the figure show the ocean floor spreading from the ridge. What are three kinds of evidence scientists have found to support this idea?
A. B. C.
I NEED HELP
Please help this is chemistry.
Answer:
C
Explanation:
the rest are trends except for Electronegativity
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
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:
(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
Atoms and ions are all the same.
Answer:
Yes they are
Explanation:
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 !
what are chiral carbon
Answer:
A chiral carbon is a carbon bonded to four different groups ( four groups as carbon forms four bonds). The molecules formed are non superimposible on its mirror image.
From smallest to largest put these in order of their atomic radius Mg, Ba,
Sr, Ca
O Ca, Mg, Ba, S
O Ra, Sr, Ca, Mg
Mg, Ca, Sr, Ra
Mg, Sr, Ra, Ca
Answer:
b
Explanation:
i jus did it