How many valence electrons do the halogens have?
A. 8
B. 6
C. 7
D. 2
Help and explain step by step if you can!
Answer:
the third one
Explanation:
if you look at it mathematically its the one that makes the most sense
what is z=9x-y solve for x
Tell how many atoms of each element are in one molecule of the substance of table salt
Answer:
Explanation:
Then, multiply the number of moles of Na by the conversion factor 6.02214179×1023 atoms Na/ 1 mol Na, with 6.02214179×1023 atoms being the number of atoms in one mole of Na (Avogadro's constant), which then allows the cancelation of moles, leaving the number of atoms of Na.Aug 15, 2020
An igneous rock floats because air bubbles became trapped when molten material erupted from an underground volcano.
How else can this rock be accurately described?
intrusive
extrusive
large crystals
coarse texture
Answer:
D coarse texture
Explanation:
An igneous rock floats because air bubbles became trapped when molten material erupted from an underground volcano. This rock can be accurately described as extrusive and the correct option is option 2.
What are igneous rocks?Igneous rocks (from the Latin word for fire) form when hot, molten rock crystallizes and solidifies. The melt originates deep within the Earth near active plate boundaries or hot spots, then rises toward the surface. Igneous rocks are divided into two groups, intrusive or extrusive, depending upon where the molten rock solidifies.
Igneous rocks can be easily identified with their texture, density, colour, and mineral composition. Its texture depends on the shape, size, time period to cool down and solidify, and the arrangement of crystals in the rock.
Therefore, an igneous rock floats because air bubbles became trapped when molten material erupted from an underground volcano. This rock can be accurately described as extrusive and the correct option is option 2.
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Bisulfite ion
What’s its ion pleaseeee helpppp meee
Answer:
An ester of sulfuric acid in which only one sulfuric acid hydroxyl group has been esterified. The product of esterification of both sulfuric acid hydroxyl groups is a sulfate ester.
Balance : Fe2O3 + Zn = Fe+ZnO
Answer:
Fe₂O₃ + 3Zn → 2Fe + 3ZnO
Explanation:
Step 1: RxN
Fe₂O₃ + Zn → Fe + ZnO
Step 2: Balance RxN
We need 2 Fe's on both sides.
We also need 3 O's on both sides.
If we multiply ZnO by 3, we will need 3 Zn's as wellFe₂O₃ + 3Zn → 2Fe + 3ZnO
what formation is the result of wind erostion
Answer:
Wind erosion abrades surfaces and makes desert pavement, ventifacts, and desert varnish. Sand dunes are common wind deposits that come in different shapes, depending on winds and sand availability.
Which object has the least kinetic energy? A. a heavy bowling ball moving quickly B. a heavy bowling ball moving slowly C. a light ping-pong ball moving quickly D. a light ping-pong ball moving slowly
Answer:
B
Explanation:
Answer:
kisses
Explanation:
mwah
What is the change of an atom of one element (atom) to an atom of different element called?
How many atoms are in 5.80 moles of He
Answer:
5.80 mol He 6.02210^23 atoms He/ 1 mol He. This cancels out moles, leaving 3.49*10^24 atoms He. Mass is used as a method of counting atoms.
The number of atoms in 5.80 moles of He is equal to 3.49 × 10²⁴ atoms.
What is Avogadro's number?Avogadro’s number is used to represent the number of entities in one mole of any substance. Generally, these entities are ions, molecules, atoms, electrons, or protons, depending upon the type of reaction or reactant and product.
The value of Avogadro’s constant is found approximately 6.022 × 10²³ mol⁻¹. This number was named after the scientist Amedeo Avogadro after his death.
Given, the number of moles of helium = 5.80
The number of atoms in one mole of He = 6.022 × 10²³
The number of atoms on 5.80 moles of He = 5.80 × 6.022 × 10²³
Total number of atoms = 3.49 × 10²⁴
Therefore, the number of atoms in 5.80 moles of Helium is 3.49 × 10²⁴ He atoms.
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Given the image below, which calculation will NOT give you the correct average atomic mas C-12 C-13 (0.6.12)+0.4.13) (60-12)+40-13) (12+12+12-12-12+12+13+13+13+13)/10 16/10) 12+(4/10) 13
Answer:
Correct Answer: B. (60⋅12)+(40⋅13)
Explanation:
Determine the percentage of calcium in Ca3(PO3)2.
Answer:
[tex]\%Ca=38.76\%[/tex]
Explanation:
Hello.
In this case, since percent compositions are computed by knowing the number of atoms of the required atom, its atomic mass and the molar mass of the compound at which it is, thus, for calcium we have:
[tex]\%Ca=\frac{3*m_{Ca}}{M_{Ca_3(PO_4)_2}} *100\%[/tex]
Thus, since calcium weights 40.08 g/mol and calcium phosphate 310.2 g/mol, the by mass percent of calcium turns out:
[tex]\%Ca=\frac{3*40.08g/mol}{310.2g/mol} *100\%\\\\\%Ca=38.76\%[/tex]
Best regards!
WHAT IS THE MASS OF AN OBJECT WHOSE
DENSITY IS 0.23 G/ML AND A VOLUME OF
22.5 ML?
Answer:
The answer is 5.18 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
volume = 22.5 mL
density = 0.23 g/mL
We have
mass = 0.23 × 22.5 = 5.175
We have the final answer as
5.18 gHope this helps you
Which of the following best identifies where long range order would be found
Answer:
in Crystalline solids
Explanation:
After assembling a gravity filtration apparatus, begin the separation of a mixture by_____it into the filter paper. Pour the entire contents of the mixture into the filter paper, ______the solid in the filter paper if needed to speed up the filtration. After all the liquid has drained through the filter paper, finish by rinsing the solid with_____.
Answer:
decanting
stirring
solvent
Explanation:
Gravity filtration consists of a pump and a filter (to be placed outside the basin, above the water level). The pump is placed in the water. Connected by a hose to the filter, water is sucked up to the device.
In the gravity-type configuration, water is sucked into the filter, which causes an imbalance between the levels of the basin and the filter: this imbalance causes the movement of water - with the dirt - from the basin to the filter via the main drain and the skimmer.
The fill in the blanks with decanting, stirring, and solvent
Gravity filtration:It comprises of a pump & a filter.The pump should be placed in the water. In the gravity-type configuration, water could be into the filter, which resulted an imbalance between the levels of the basin and the filter: this imbalance causes the movement of water.
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2. A shopper in a supermarket takes a box of sugar from a shelf that is 1.5 m high because he is
going to bake some muffins. He also needs to get some blueberries. The sugar has a weight of 5N.
What Potential Energy did the sugar have before it was taken from the shelf?
Explanation:
kinetic energy?? idek hope I helped in anyway possible
Answer:
7.5 joules also 7.5 J
Explanation:
When two hydrogen nuclei combine to form one helium nucleus, nuclear fusion has taken place. true or false??
please help i need to know asap!
Answer:
sorry im just doin it for the points but i rlly dont know
Explanation:
At a certain temperature the rate of this reaction is first order in with a rate constant of : Suppose a vessel contains at a concentration of . Calculate the concentration of in the vessel seconds later. You may assume no other reaction is important. Round your answer to significant digits.
Complete question is;
Consider this reaction: 2 HI(g) ⇄ H₂(g) + I₂(g)
At a certain temperature, this reaction follows first - order kinetics with a rate constant of 0.684 s^(-1). Suppose a vessel contains HI at a concentration of 0.32 M. Calculate the concentration of HI in the vessel 0.88 seconds later.
You may assume no other reaction is important.
Round your answer to 2 significant digits
Answer:
0.18 M
Explanation:
We are given;
Initial concentration of HI = 0.32 M
Time = 0.88 s
Rate is given as 0.684 s^(-1)
Now, we want to find the concentration of HI in the vessel 0.88 seconds later. It can be gotten from the formula;
ln (HI) = ln (HI)₀ - (kt)
Where;
(HI)₀ is the initial concentration
k is the reaction rate constant
t is time
Plugging in the relevant values, we have;
ln (HI) = In (0.32) - (0.684 × 0.88)
ln (HI) = -1.1394 - 0.6019
ln (HI) = -1.7413
(HI) = e^(-1.7413)
(HI) = 0.175 M ≈ 0.18 M
Control of Blood pH by respiratory rate.
A) The partial pressure of CO2 in the lungs can be varied rapidly by the rate and depth of breathing. For example, a common remedy to alleviate hiccups is to increase the concentration of CO2 in the lungs. This can be achieved by holding one’s breath, by very slow and shallow breathing (hypoventilation), or by breathing in and out of a paper bag. Under such conditions, pCO2 in the air space of the lungs rises above normal. Qualitatively explain the effect of these procedures on the blood pH.
B) A common practice of competitive short-distance runners is to breathe rapidly and deeply (hyperventilate) for about half a minute to remove CO2 from their lungs just before the race begins. Blood pH may rise to 7.60. Explain why the blood pH increases.
C) During a short-distance run, the muscles produce a large amount of lactic acid (CH2CH(OH)COOH; K2 = 1.38 × 10–4M) from their glucose stores. Why might hyperventilation before a dash be useful?
Answer:
A) During this procedure ( hypoventilation ) The CO2 in the arterial blood vessels and the lungs increases and this drives the PH level in the system lower, and the equilibrium will shift to the right. this is because the Blood-PH level is controlled by CO2 - bicarbonate buffer system
B) The blood PH may rise to 7.60 during Hyperventilation because the removal of CO2 from the lungs causes the increase in [tex]H^+[/tex] which is directly proportional to the increase in Blood PH levels
C) Hyper ventilation before a dash would be useful because it will remove excessive Hydrogen ions and and raise the Blood PH levels in preparedness of the production of acids like Lactic acid
Explanation:
A) During this procedure ( hypoventilation ) The CO2 in the arterial blood vessels and the lungs increases and this drives the PH level in the system lower, and the equilibrium will shift to the right. this is because the Blood-PH level is controlled by CO2 - bicarbonate buffer system
[tex]CO_{2} +H_{2} O[/tex] ⇄ [tex]H^+ + HCO^-_{3}[/tex]
B) The blood PH may rise to 7.60 during Hyperventilation because the removal of CO2 from the lungs causes the increase in [tex]H^+[/tex] which is directly proportional to the increase in Blood PH levels
C) Hyper ventilation before a dash would be useful because it will remove excessive Hydrogen ions and and raise the Blood PH levels in preparedness of the production of acids like Lactic acid
Ms. Lewis is a chemist micing two solutions together. A chemical reaction takes place, and the solution becomes warm. Which statement best describes what has happened?
O Energy has been created in the form of thermal energy.
O Energy has been transformed from one form to another
More energy has been created than has been destroyed.
a The chemical energy of the solution has been destroyed.
Answer:
It would have to tp be "Energy is being transformed from one form to another".
Explanation:
The reason I know this is because energy can neither be created nor destroyed only transformed into new forms.
Answer:
Energy has been transferred from one form to another.
Explanation:
got it right
If you are 5 foot 10 inches, how tall are you in meters? Meters ( write you answer 4 significant figures e.g. 2.852)
Why is the reaction of a strong acid and a strong base classified as a neutralization reaction?
a. Water and a salt are produced, leaving the pH of the solution at a very high value.
b. Only water is produced, and water has a pH of 7.0.
c. Water and a salt are produced, leaving the pH of the solution at a value of 7.0.
d. Water and a salt are produced, leaving the pH of the solution at a very low value.
Answer:
Answer choice C
Explanation:
Basicly for the Arrhenius and Bornsted-Lowery theories of acids & bases, acid-base reactions can be divided into 4 forms...
a. Strong Acid + Strong Base (HCl/NaOH) => pH = 7 at Eqv. Pt.
b. Weak Acid + Strong Base (HOAc/NaOH) => pH > 7 at Eqv. Pt.
c. Strong Acid + Weak Base (HCl & NH₄OH) => pH < 7 at Eqv. Pt.
d. Weak Acid + Weak Base (HOAc & NH₄OH) => pH ∝ Stronger Electrolyte
*HOAc = Acetic Acid
*NH₄OH = Ammonium Hydroxide
For each type reaction the pH at equivalence point depends upon the salt generated by the acid-base reaction. Ions of the salt, if they react with water, (hydrolysis) will shift the pH up or down depending upon which ion reacts. If there is no reaction by the salt ions then the pH will depend only upon autoionization of water which gives pH = 7. Typically Strong Acids + Strong Bases will give a pH = 7 at equivalence point because the ions of the salt will not undergo hydrolysis in water.
Example:
Strong Acid + Strong Base
HCl(aq) + NaOH(aq) => NaCl(aq) + H₂O(l)
NaCl(aq) => Na⁺(aq) + Cl⁻(aq)
Na⁺(aq) + H₂O(l) => No Rxn (theoretically NaOH, but NaOH is a strong base which prefers to remain 100% ionized in water).
Cl⁻(aq) + H₂O(l) => No Rxn (theoretically HCl, but HCl is a strong acid which prefers to remain 100% ionized in water).
Therefore, the net rxn is H⁺ + OH⁻ => H₂O & pH = 7.0
Weak Acid + Strong Base
HOAc(aq) + NaOH(aq) => NaOAc(aq) + H₂O(l)
NaOAc(aq) => Na⁺(aq) + OAc⁻(aq)
Na⁺(aq) + H₂O(l) => No Rxn
OAc⁻(aq) + H₂O(l) => HOAc(aq) + OH⁻(aq) => (Excess OH⁻ functions to increase pH>7 at eqv. pt.)
Strong Acid + Weak Base
HCl(aq) + NH₄OH(aq) => NH₄Cl(aq) + H₂O(l)
NH₄Cl(aq) => NH₄⁺(aq) + Cl⁻(aq)
Cl⁻(aq) + H₂O(l) => No Rxn
NH₄⁺(aq) + H₂O(l) => NH₄OH(aq) + H⁺(aq) => (Excess H⁺ functions to decrease pH < 7 at eqv. pt. )
household items that are substances
Answer:
water,salt are the house hold items
a mechanical pencil has the mass of 55.5 grams the volume of the pencil is 11.5 cubic centimeter what is the density of the pencil
Answer:
D = M/V
Explanation:
D = 55.5g/11.5cm^3
D = 4.83g/cm^3
Identify the term that applies to each definition.
A. A sample prepared using the solvent and any other chemicals in the sample solutions, but not the absorbing substance
B. A square-shaped container, typically made of quartz, designed to hold samples in a spectrophotometer
C. A measurement of the amount of light that passes through a sample
D. A measurement of the amount of light taken in by a sample
E. A unit commonly used in spectrophotometry that is inversely proportional to energy and commonly measured in nanometers
Answer:
A. Reference blank
B. Cuvettes
C. Transmittance
D. Absorbance
E. Wavelength
Explanation:
A reference blank is a sample prepared using the solvent and any other chemicals in the sample solutions, but not the absorbing substance.
A square-shaped container, typically made of quartz, designed to hold samples in a spectrophotometer is known as Cuvettes.
A measurement of the amount of light that passes through a sample or percentage of light transmitted by the sample, with the respective intensities of the incident and transmitted beams is called Transmittance.
The measurement of the amount of light taken in by a sample is known as Absorbance
The wavelength is also the distance travelled by the wave during a period of oscillation. In spectrophotometry, the unit is inversely proportional to energy and commonly measured in nanometers
The sample that is prepared using the solvent and any other chemicals in the sample solutions, but not the absorbing substance is a reference blank.
A square-shaped container, typically made of quartz, designed to hold samples in a spectrophotometer is the cuvettes.
A measurement of the amount of light that passes through a sample is transmittance.
A measurement of the amount of light that is taken in by a sample is referred to as absorbance.
A unit that is commonly used in spectrophotometry that is inversely proportional to energy and commonly measured in nanometers is the wavelength.
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Explain what happens to the particles in a substance during a physical change. plllzzzzz hurry!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Answer:
When a physical change occurs, the arrangement of particles within the substance may change, but the atoms in the molecules remain bonded together.
Explanation:
Srry didn't see this till now, hope u got it right :)
which statement about the sun is true?
A.The sun is a red giant
B. The sun will become a red giant
C. The sun began as a red giant
D. The sun cannnot become a reg giant
In x-ray studies of crystalline peptides, Linus Pauling and Robert Corey found that the C—N bond in the peptide link is intermediate in length (1.32 Å) between a typical C—N single bond (1.49 Å) and a C=N double bond (1.27 Å). They also found that the peptide bond is planar (all four atoms attached to the C—N group are located in the same plane) and that the two α-carbon atoms attached to the C—N are always trans to each other (on opposite sides of the peptide bond).
Required:
a. What does the length of the C—N bond in the peptide linkage indicate about its strength and its bond order (i.e., whether it is single, double, or triple)?
b. What do the observations of Pauling and Corey tell us about the ease of rotation about the C—N peptide bond?
Answer:
The C-N bond is a double bond.
There is no free rotation about the C-N bond
Explanation:
Linus Pauling and Robert Corey carried out a painstaking study of the bond lengths of peptide bonds as well as the stereo chemistry of atoms and groups around the peptide bonds in the crystal structures of molecules containing one or a few peptide bonds.
Their findings indicate that the bond length of the C-N bond in crystalline peptides is intermediate in length (1.32 Å) between a typical C—N single bond (1.49 Å) and a C=N double bond (1.27 Å). This is because the peptide bond has some double bond character as a result of resonance involving the C=O and -NH moieties of the amide.
As a result of resonance as shown above, the peptide bonds are found to be planar hence free rotation about the C-N bond is hindered. The peptide bond is mostly found in the trans configuration because it is more energetically favourable than the cis configuration.
Summarily, owing to the existence of a partial double bond character between the α carbon and the amine nitrogen in the peptide, there is no free rotation around the C-N bond.
In addition to specialized glassware and tools, there are several other considerations required for the setup of a distillation apparatus.
Before assembling a distillation apparatus, lubricate the ground glass joints of each piece of glassware using _______. This helps seal the connection between two components. Once two components are fit together, use ________ to make the connections secure. Stabilize the complete distillation setup using a _______.
Answer: Grease; Clamp; Ring stand.
Explanation:
Distillation is being used while separating liquids from the nonvolatile solids, or in instance whereby there is a different boiling point between two or more liquids.
Before assembling a distillation apparatus, lubricate the ground glass joints of each piece of glassware using grease. This will help in lubricating the glass joints so that it won't squeeze out while under pressure.
This helps seal the connection between two components. Once two components are fit together, use clamp to make the connections secure. Clamp is a fastening device which will help in holding the components together so that they won't be separated.
Stabilize the complete distillation setup using a ring stand. The ring stand will help in the provision of support to the glassware.