Answer:
B. H2CO3 and KHCO3
Explanation:
The buffer system is a system in which the solution deny for change in the ph level i.e. at the time when the acid is added to it. It can be made either in a weak acid and salt or can be a weak base and its salt. Now when the acid is added to a buffer so the ratio is not impacted due to which it does not change sufficient for pH level
As per the given options, the third one is correct as the H2CO3 denotes a weak acid and the KHCO3 represents the salt. And these two solution does not create any change in the level of pH
Therefore the option B is correct
23
A solid is insoluble in water but dissolves in aqueous acid and in aqueous alkali without
evolution of a gas in either case. What could the solid be?
A
B.
с
D
copper(II) carbonate
copper(II) hydroxide
zinc carbonate
zinc hydroxide
Answer:
copper(II) carbonate
What determines the reactivity of an akali metal?
Answer:
The number of valence electrons determines an element's reactivity, or how likely the element is to react with other elements.
Explanation:
Identify the polyatomic ion and its charge in each compound (a) KNO2 K N O 2 (b) CaSO4 C a S O 4 (c) Mg(NO3)2
Answer:
Explanation:
Polyatomic ions are ions (usually anions) that are made up of more than one atom. In order to determine the charge of anions, one can first identify the charge of the metal (which forms the cation) in a compound (which is usually easy to know) before predicting the charge of the anion. The charges are usually exchanged to form denominator of the other reacting atom/molecule, but if divisible, they are divided first before the exchange.
(a) The polyatomic ion in KNO₂ is NO₂ with the ionic equation below showing it's charge
KNO₂ ⇒ K⁺ + NO₂⁻
From the above, we can deduce that the charge of NO₂ is "1-"
(b) The polyatomic ion in CaSO₄ is SO₄ with the ionic equation below showing it's charge
CaSO₄ ⇒ Ca²⁺ + SO₄²⁻
The charge of SO₄ from the above equation is "2-"
(c) The polyatomic ion in Mg(NO₃)₂ is NO₃ with the ionic equation below showing it's charge
Mg(NO₃)₂ ⇒ Mg²⁺ + NO₃⁻
From the above equation, it can be deduced that the charge of NO₃ is "1-"
The density of silver is 10.5 g/cm3. What is the mass (in kilograms) of a cube of silver that measures 0.94 m on each side?
Answer:
8721.132 Kg.
Explanation:
The following data were obtained from the question:
Density (D) of silver = 10.5 g/cm³
Length (L) of silver = 0.94 m
Mass (m) of silver =.?
Next, we shall determine the volume of silver. This can be obtained as follow:
Volume = Length × Length × Length
Volume = L × L × L
Volume = L³
Length (L) of silver = 0.94 m
Volume (V) of silver =?
Volume (V) of silver = 0.94³
Volume (V) of silver = 0.830584 m³
Next, we shall convert 0.830584 m³ to cm³. This can be obtained as follow:
1 m³ = 1×10⁶ cm³
Therefore,
0.830584 m³ = 0.830584 m³ / 1 m³ × 1×10⁶ cm³
0.830584 m³ = 830584 cm³
Therefore, 0.830584 m³ is equivalent 830584 cm³.
Thus, the volume of the silver is 830584 cm³.
Next, we shall determine the mass of the silver. This can be obtained as follow:
Density (D) of silver = 10.5 g/cm³
Volume of the silver = 830584 cm³.
Mass of silver =.?
Density = mass /
10.5 = mass of silver /830584
Cross multiply
Mass of silver = 10.5 × 830584
Mass of silver = 8721132 g
Finally, we shall convert the mass of silver, 8721132 g to kilogram (kg). This can be obtained as follow:
1000 g = 1 Kg
Therefore,
8721132 g = 8721132 g / 1000 g × 1 Kg
8721132 g = 8721.132 Kg
Therefore, the mass of each cube of silver is 8721.132 Kg
12.A piece of magnesium is in the shape of a cylinder with a height of 5.62 cm
and a diameter of 1.34 cm. If the magnesium sample has a mass of 14.1 g, what
is the density of the sample?
Answer:
Density, d = 1.779 g/cm³
Explanation:
The density of a material is given by its mass per unit volume.
Here, height of a piece of magnesium cylinder, h = 5.62 cm
Its diameter, d = 1.34 cm
Radius = 0.67 cm
Volume of he cylinder,
[tex]V=\pi r^2 h\\\\\text{Putting the value of r and h, we get :}\\\\V=(\pi \times (0.67)^2\times 5.62)\ cm^3[/tex]
[tex]d=\dfrac{m}{V}\\\\d=\dfrac{14.1\ g}{(\pi \times (0.67)^2\times 5.62)\ cm^3}\\\\d=1.779\ g/cm^3[/tex]
So, the density of the sample is 1.779 g/cm³.
Can someone please help me with this? :(
Answer:
Bo
Explanation:
Bo is not a element
Complete the chemical combustion reaction of naphthalene, which
demonstrates the conservation of mass.
C10H8 + 1202 >>
Answer:
[tex]C_{10}H_{8}+12O_2\rightarrow 10CO_2+4H_2O[/tex]
Explanation:
Hello,
In this case, since combustion reactions yield carbon dioxide and water via the following equation:
[tex]fuel+O_2\rightarrow CO_2+H_2O[/tex]
In such a way, for naphthalene, its combustion reaction is:
[tex]C_{10}H_{8}+12O_2\rightarrow 10CO_2+4H_2O[/tex]
Whereas we see ten carbon atoms, eight hydrogen atoms and twenty four oxygen atoms at both reactants and products as a proof of the law conservation of mass.
Regards.
Which of the following is true concerning y? A) wdescribes the probability of finding an electron in space. B) ya describes the exact path of electron motion in an orbital. C) w? describes the electronic structure of the atom according to the Bohr model. D) w describes the exact volume of an atom. E) w2 describes the size of an atom.
Answer:
wdescribes the probability of finding an electron in space.
Explanation:
The quantum mechanical model of the atom assigns wave properties to the electron. This is in accordance with Heisenberg's uncertainty principle.
The probability of finding the electron in a given volume element is given as the square of the wave function while the wave function itself does not really have a physically significant meaning.
However, the wave function is a mathematical function that contains a detailed information about the behavior of an electron.
How does the number of valence electrons in atoms of metalloids explain why metalloids are semiconductors? They have one or two valence electrons, so they cannot lose electrons easily. They have one or two valence electrons, so they can lose or gain electrons. They have three to six valence electrons, so they cannot lose electrons easily. They have three to six valence electrons, so they can lose or gain electrons.
Answer:
They have three to six valence electrons, so they can lose or gain electrons.
Explanation:
Here, we are required to identify how the number of Valence electrons on atoms of metalloids explain why metalloids are semiconductors.
This is because; They have three to six valence electrons, so they can lose or gain electronsMetalloids are elements in the periodic table which are characterized by the the presence of 3 to 6 Valence electrons.
Metalloids unlike Alkali and alkali earth metals (which have 1 and 2 Valence electrons and are highly electropositive) and halogens( with valency of 7 and are highly electronegative) have three to six valence electrons and are therefore able to lose or accept electrons.Ultimately, the presence of three to six Valence electrons and the ability to either lose or gain electrons is the criteria for their semiconductor character.
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Decaying plants and animals are important to an ecosystem because they
A.
cause disease in living organisms.
B.
reduce soil erosion.
C.
recycle oxygen to the air.
D.
return nutrients to the soil.
Answer:
The option D is correct answer.
Decaying pants and animals are important to the ecosystem as they return the nutrients to the soil.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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at what height is an object that has a mass of 16kg, if it’s gravitational potential energy is 7500J?
Answer:
46.875
Explanation:
P.E=MGH
7500=16*10*h
7500=160h
h=7500/160
h=46.875
How many cm are in 29.7km?
Answer:
there are 2970000cm in 29.7km
Explanation:
Oxalic acid, H2C2O4*2H2O (molar mass = 126.07 g/mol) is oftenused as a primary standard for the standardization of a NaOHsolution. If 0.147 g of oxalic acid dihydrate is nutralizedby 23.64mL of a NaOH solution, what is the molar concentration ofthe NAOH solution? Oxalic acid is a diprotic acid. (What is thebalanced equation?)
Answer:
0.09865M of NaOH
Explanation:
As a diprotic acid, 1 mole of oxalic acid reacts with 2 moles of NaOH as follows:
H2C2O4 + 2 NaOH → 2 H2O + Na2C2O4
With the mass of the acid and its molar mass we can obtain the moles of oxalic acid. Twice these moles are the moles of NaOH in the solution. As you required 23.64mL = 0.02364L of the NaOH, you can knkow molarity, thus:
Moles Oxalic acid:
0.147g * (1mol / 126.07g) = 1.166x10⁻³ moles Oxalic acid.
Moles NaOH:
1.166x10⁻³ moles Oxalic acid * (2 moles NaOH / 1 mole H2C2O4) = 2.332x10⁻³ moles NaOH
Molarity:
2.332x10⁻³ moles NaOH / 0.02364L =
0.09865M of NaOHWhich wave has the greatest distance from trough to trough?
Answer:
C.C
Explanation:
Just took the test
A transverse wave is a motion in which all points on a wave oscillate along paths at right angles. Hence, option C is correct.
On a wave, what is the distance from trough to trough?The wavelength is the horizontal distance between two adjacent crests or troughs.
The longest distance a particle goes from rest is to the peak of a crest or the bottom of a trough in a transverse wave. The amplitude of a transverse wave is this distance.
Hence, option C is correct.
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You have two compounds that you have spotted on the TLC plate. One compound is more polar than the other. You ran the TLC plate with neat hexanes and found that only one spot moved a small distance up the plate. What might you expect to see if you ran a TLC plate in a 50/50 mixture of hexanes and ethyl acetate
Answer:
we will except an increase in the polarity of the system and this will cause the Non-polar spot to be near the solvent front, while the polar spot will run at an approximate speed of 0.5 Rf
Explanation:
when we run a TLC plate in a 50/50 mixture of hexanes and ethyl acetate we will except an increase in the polarity of the system and this will cause the Non-polar spot to be near the solvent front, while the polar spot will run at an approximate speed of 0.5 Rf
The speed of the polar spot depends largely on the level of polarity, an increase in the polarity will see both spots of Neat hexane run when we run a TLC plate in a 50/50 mixture of hexanes and ethyl acetate
Calculate the time,speed is 100m/s and distance is 2000 meter
Explanation:
Time = Distnace ×speed
so distance is 2000m
and speed is 100
so 100×2000
time = 200000s
Draw the line-bond structure of oleic acid (cis-9-octadecenoic acid), CH3(CH2)7CH=CH(CH2)7COOH, at physiological pH. You do not need to draw hydrogen atoms attached to carbon atoms.
Answer:
Explanation:
Oleic acid originates from an unsaturated fatty acid with 18 carbon atoms and one double bond, which can be found in olive oil and many other vegetable and animal oils and fats. Its economic importance includes the production of soap making and cosmetics etc.
The line-bond structure of the given oleic acid in the question can be found in the attached below.
The line-bond structure of oleic acid is given in the image attached. The line-bond structure represents the number of carbon atoms.
Oleic acid:Oleic acid is an omega-9 fatty acid. It can be made by the body. It is also found in foods. Highest levels are found in olive oil and other edible oils. Oleic acid is most commonly used for preventing heart disease and reducing cholesterol. It is long chain of 18 Carbon atoms.
It is found in oils such as olive, palm, peanut, and sunflower.
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Metal atoms always form a cation of a single, specific charge.
a.) True, because metal atoms form ionic compounds of a known composition.
b.) False, because some metal atoms are known to have more than one possible positive charge.
c.) True, because nonmetal atoms always form anions of a single, specific charge.
d.) True, because metal atoms lose all of their valence electrons.
e.) False, because elements in different rows of the periodic table can form different cations.
Answer:
c.) true, because nonmetal atoms always form anions of a single , specific charge
What has more
mass, a mole of
sodium chloride
or 2 moles of
aluminum?
Answer:
2 moles of aluminum
Explanation:
calculate the density, in g/mL, of a liquid that has a mass of 0.165 g and a volume of 0.000295 l
Answer:
The answer is
0.56 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question
mass of liquid = 0.165 g
Next we change the volume from L to mL using the conversion
1 L = 1000 mL
We have
If 1 L = 1000 mL
Then 0.000295 l = 1000 × 0.000295
volume = 0.295 mL
The density is
[tex]density = \frac{0.165}{0.295} \\ = 0.55932203...[/tex]
We have the final answer as
0.56 g/mLHope this helps you
The particles of a gas inside a balloon are experiencing an increase in their average kinetic energy and the number of collisions with the wall of the balloon. What is the most likely outcome? higher gas pressure inside the balloon higher air pressure outside the balloon a decrease in gas temperature inside the balloon a large increase in air temperature outside the balloon
The higher Gas pressure inside the balloon. Hence, option A is correct.
How is kinetic energy related to temperature?In a molecule, the kinetic energy existing is "directly proportional" to the temperature of the molecule. If one of the values increases, then the other value also increases and vice-versa.
The higher Gas pressure inside the balloon. As the number of collisions with the wall of the balloon increases, the pressure inside increases.
Hence, option A is correct.
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help whats 2+2 i really don't know what the answer is i think it 1,250 but idk
Answer:
its 4
Explanation:
Answer:
4 is the answer
Explanation:
2 fingers plus 2 fingers is 4 fingers, Not 1,250
Complete hydrolysis of a hexapeptide gives 2 Gly, Leu, Phe, Pro, and Tyr. Reaction of the peptide with phenylisothiocyanate gave the phenylthiohydantoin of Pro. Partial hydrolysis of the peptide gave the following fragments: Phe-Gly-Tyr, Gly-Phe-Gly, Pro-Leu-Gly, Leu-Gly-Phe. What is the structure of the peptide
Answer:
The complete sequence : Pro-Leu-Gly-Phe-Gly-Tyr
Explanation:
For the formation of phenylisothiocyanate, the four peptide sequences overlap common residue to get the the complete sequence of the hexapeptide as shown in the diagram attached below
Attached below is the structure of the peptide
An unopened 350 mL can of diet Dr. Pepper will float in a lake. However, it’s also true that an unopened 350 mL can f regular Dr. Pepper will sink in the same lake! Based on these two facts, which type of soda is the least dense? Explain your answer.
Answer:
Diet Dr. Pepper
Explanation:
The density of an object and the liquid involved determines if that particular object will float or sink in the particular liquid. An object will FLOAT if its density is lower than that of the liquid substance while it will SINK if its density is higher than that of the liquid substance.
In this case, water (lake) is the liquid substance. According to the question, an unopened 350 mL can of DIET Dr. Pepper will float in a lake because it is less dense than the water while an unopened 350 mL can of REGULAR Dr. Pepper will sink because it is more dense than water.
Hence, the DIET type of soda is the least dense
Solve: (6.825 x 10-3) (1.2 x 10-8)
Choose the answer with the correct number of significant figures.
a 8.2 x 10-11
b 0.081 x 10-8
C 8.01 x 1011
d None of the above
Answer: a.) 8.2 x 10^-11
Explanation:
Why does burned toast taste so bad? Is it a chemical or physical change?
Because things that are burnt have been changed into something else like moldy bread thats cooked.
It is chemical change because you cannot unburn something.
Answer:
It's a chemical change because I'm really good at answers
Explanation:
What is the mass, in grams, of 1.33 mol of water, H2O?
Answer:
24.0g H2O
Explanation:
1.33 mol (18.016g/1 mol) = 24.0g H2O
Calculate the percent composition for each of the elements in Na3PO4. A 5.00 gram sample of an oxide of lead PbxOy contains 4.33 g of lead. Determine the simplest formula for the compound. Balance the following equations by inspection: Cu(N03)2 rightarrow CuO + NO2 + O2 C2H6 + O2 rightarrow CO2 + H2O Mg3N2 + H2O rightarrow Mg(OH)2 + NH3 Magnesium (Mg) reacts with chlorine gas (C12) to produce magnesium chloride (MgC12). How many grams of Mg will react with 2 moles of Cl2? Mg(s) + C12(g) rightarrow MgC12(s) The compound P4S3 is used in matches. It reacts with oxygen to produce P4O10 and SO2. The unbalanced chemical equation is shown below, P4S3(s) + O2(g) rightarrow P4O10(s) + SO2(g) What mass of SO2 is produced from the combustion of 0.331 g P4S3 in excess O2? Nitric oxide is made from the oxidation of ammonia. What mass of nitric oxide can be made from the reaction of 8.00 g NH3 with 17.0 g O2? 4 NH3(g) + 5 O2(g) rightarrow 4 NO(g) + 6 H2O(g) To what volume should you dilute 50.0 mL of 12 M HNO3 solution to obtain a 0.100 M HNO3 solution?
Answer:
1. Percentage composition of: Na = 42%; P = 19.0%; O = 39%
2. Simplest formula of compound is PbO₂
3. (i) 2Cu(NO₃) ---> 2CuO + 2NO₂ + 3O₂
(ii) 2C₂H₆ + 7O₂ ---> 4CO₂ + 6H₂O
(iii) Mg₃N₂ + 6H₂O ---> 3Mg(OH)₂ + 2NH₃
4. 48 g of MG will react with 2 moles of Cl₂
5. 0.288 g of SO2 will be produced from the combustion of 0.331 g P₄S₃ in excess O₂
6. 12.8 g of nitric oxide can be produced from the reaction of 8.00 g NH₃ with 17.0 g O₂
7. The stock acid solution should be diluted to 6000 mL or 6.0 L
Explanation:
The full explanation is found in the attachments below
A bird flies 3.7 meters in 46 seconds, what is its speed?
v=
d=
t=
Answer:
speed = 3.7/46 = 0.080m/s
d= 3.7m
t= 46s
Explanation:
Sample of carbonate rock is a mixture of CaCO3 and MgCO3. The rock is Analyzed in a laboratory and the results are recorded in the table above. Which columns in a table provide all the information necessary to determine the mole ratio of analyzed in a laboratory and the results are recorded in the table above. Which columns in a table provide all the information necessary to determine the mole ratio of Ca to Mg in the rock
Answer:
You need the mass of Mg and Ca in the sample and their molar masses
Explanation:
Its the only answer that made sense because using those 4, can give you their ration
The Columns in the table that provides the information necessary for the calculating the mole ratio of Ca to Mg are columns ; 3, 4, 6, and 7
Although some data related to your question is missing attached below is the missing data
Determining the mole ratio of Ca to Mg
Ca : Mg
mass of Ca / molar mass : mass of Mg / Molar mass
( 36.1 / 40.1 ) : ( 2.4 / 24.3 )
9.14 : 1
∴ The mole ratio of Mg to Ca
≈ 1 : 9
Where: Column 3 = Mass of Mg in the sample ( g )
Column 4 = mass of Ca in the sample ( g )
Column 6 = Molar mass of Mg ( g/mol )
Column 7 = molar mass of Ca ( g/mol )
Hence the Mole ratio of Mg to Ca = 1 : 9
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