Answer:
2.place value is 70 000 00
A 0.90 g of hydrogen chloride (HCl) is dissolved in water to make 5.0 L of solution. What is the pH of the resulting hydrochloric acid solution?
Express the pH numerically to two decimal places.
0.50g of sodium hydroxide (NaOH) pellets are dissolved in water to make 4.0L of solution. What is the pH of this solution?
Express the pH numerically to two decimal places.
Answer:
Explanation:
Mol weight of HCl = 36.5
.90 g of HCl = .90 / 36.5 mole = .02465 mole
HCl = H⁺ + Cl⁻
1 mole 1 mole
1 mole of HCl gives 1 mole of H⁺
.02465 mole of HCl will give .02465 mole of H⁺
.02465 mole of H⁺ in 5 litre soln
concentration of H⁺ = .02465 / 5 = 4.93 x 10⁻³ M
pH = - log ( 4.93 x 10⁻³ )
= 3 - log 4.93
= 3 - .693
= 2.307
= 2.31
NaOH :
Mol weight of NaOH = 40
.50 g of HCl = .50 / 40 mole = .0125 mole
NaOH = Na⁺ + OH⁻
1 mole 1 mole
1 mole of NaOH gives 1 mole of OH⁻
.0125 mole of NaOH will give .0125 mole of OH⁻
.0125 mole of OH⁻ in 4 litre soln
concentration of OH⁻ = .0125 / 4 = 3.125 x 10⁻³ M
pOH = - log ( 3.125 x 10⁻³ )
= 3 - log 3.125
= 3 - .495
= 2.505
pH = 14 - pOH
= 14 - 2.505
= 11.495 .
= 11.50
Determine whether each observation generally corresponds to a physical change or a chemical change. A liquid freezes into a solid. _________ Bubbles are produced upon mixing two solutions. __________ A precipitate is formed from two solutions. _________ A solution heats up upon mixing with another. ____________ A solid dissolves into water. __________ The color of a substance changes over time
Answer:
A liquid freezes into a solid or any other state change is a physical change. Bubbles are produced upon mixing two solutions is a Chemical change as gas formed. a precipitate is formed from two solutions is a Chemical change The conversion of a substance to another compound over time leads to a color change of the substance due to the insolubility of the compound.
It is a chemical change or properties. A solution that heats up upon mixing with another is a Chemical change known as an exothermic reaction. dissolving the substance in a liquid is a physical change physical that can be regained by evaporation or crystalization.
what information is shown in the infographics?
Answer:
An infographic is a collection of imagery, charts, and minimal text that gives an easy-to-understand overview of a topic. As in the example below, infographics use striking, engaging visuals to communicate information quickly and clearly. Infographics are a valuable tool for visual communication.
Suppose you are titrating an acid of unknown concentration with a standardized base. At the beginning of the titration, you read the base titrant volume as 2.49 mL. After running the titration and reaching the endpoint, you read the base titrant volume as 22.98 mL. What volume, in mL, of base was required for the titration?
Answer:
The volume required for the titration is 20.49mL.
Explanation:
In a titration of an acid, you must fill the burette until a particular volume (In the problem, the burette is filled until 2.49mL).
Then, when the titration is ran, the final volume helps to find the volume required to the titration as follows:
Volume of titration = Final Volume - Initial volume
Volume of titration = 22.98mL - 2.49mL = 20.49mL
The volume required for the titration is 20.49mLLocal winds can be caused by______heating of the earth's surface.
equal
ground
uneven
super
A compound or material formed by a chemical reaction is know as the of the reaction
Answer:
reactants
Explanation:
please give brainlist
Answer:
Reactant
Explanation:
DECREASES the erosion of agricultural lands.
A)
Planting cover crops
B)
Allowing the land lie fallow
c)
Alternating planting and grazing
D)
Plowing the land several months before planting
Answer:
I would say A. to be honest
A solvent was composed of two separate components: water and cyclohexane. If ethyl acetate was added to the solvent, into which layer would it most likely dissolve? Explain?
Answer:
water
Explanation:
In chemistry, an important principle that guides the solubility of a solute in a solvent is the principle of like dissolves like.
A polar solvent will dissolve a polar solute and a non-polar solvent will dissolve a non polar solute.
Ethyl acetate is a polar solute. It will have to dissolve in water which is a polar solvent. Hence, ethyl acetate will dissolve in the water layer.
How many bonds are formed when the following atoms combine?
a) Hydrogen and oxygen in water
b) Hydrogen and chlorine in hydrogen chloride
c) Hydrogen and carbon in methane
Answer:
the answer is a I think
Explanation:
Mixture of water and non-dissolved materials.
A mixture of water and non-dissolved materials is called a heterogeneous mixture.
A heterogeneous mixture is a mixture that contains two or more substances that are not uniformly distributed throughout the mixture.
In a mixture of water and non-dissolved materials, the non-dissolved materials are not uniformly distributed throughout the water. Instead, they will settle to the bottom of the container over time.
Therefore, heterogeneous mixture is a mixture of water and non-dissolved materials.
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Which of these describes a Mole in Chemistry?
A. A counting term for substances
B. The Molar mass of substance in grams
C. 6.02 x 10^23
D. All of the above describe a mole
Answer: Thus the correct option is D. All of the above describe a mole
Explanation:
According to avogadro's law, 1 mole of every substance weighs equal to molecular mass in grams.
1 mole of every substance contains avogadro's number [tex]6.023\times 10^{23}[/tex] of particles.
Mole is the S.I unit for measuring the amount of substance. It is often used to measure large number of particles.
Thus the correct option is D. All of the above describe a mole
Explain the flow of energy needed to bring electrical energy to the city.
Answer:
The electricity that flows to our homes is generated in the power station from here it flows through large transmission line which carry it to substations finally distribution carry electricity from substations to homes schools etc
The atoms in a copper bar are held together by metallic bonding. What would happen you ran over a copper bar with a car? It would . A. shatter B. become a covalent compound C. become an ionic compound D. be bent or flattened into a different shape
The answer is D.
Hope this helps!
Answer:
i would say D mostly because I don't know what the other ones mean
Explanation:
(just looked them up and I still think its D)
Based on the following equation, how many moles of hydrochloric acid (HCl)are needed to react with 0.44 moles of potassium
permanganate (KMnO4)?
2KMnO4 + 8HCI - 3Cl2 + 2MnO2 + 4H2O + 2KCI
Answer:
1.76 moles of HCl.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
2KMnO₄ + 8HCl —> 3Cl₂ + 2MnO₂ + 4H₂O + 2KCl
From the balanced equation above,
2 moles of KMnO₄ reacted with 8 moles of HCl.
Finally, we shall determine the number of mole of HCl needed to react with 0.44 moles of KMnO₄. This can be obtained as follow:
From the balanced equation above,
2 moles of KMnO₄ reacted with 8 moles of HCl.
Therefore, 0.44 moles of KMnO₄ will react with = (0.44 × 8)/2 = 1.76 moles of HCl.
Thus, 1.76 moles of HCl is needed for the reaction.
What is it called when instead of getting rid of a product you find another
use for the product?
Answer:
Recycling.
Explanation:
When instead of getting rid of a product you find another use for the product, it is called recycling.
Recycling can be defined as a process which typically involves gathering, processing and transformation of materials or products that would otherwise be gotten rid of as waste materials or trash into new products that could be used for another purpose.
Basically, the recycling process involves turning a trash or unwanted product into a treasure (new product) that is capable of serving another purpose.
For example, the crown cork of a bottle could be gathered and processed into art forms that can be used for decorations.
Convert 10.0 g of iron (II) sulfate to moles.
please explain how to do this! I don't understand
Explanation:
number of moles =mass /relative molecular mass
n=10g/mr(FeSO4)
N=10/(56+32+16×4)
N=10/152
N=0,066 moles
The electrical current in a circuit is measured in which of the following units
Answer:
joules
Explanation:
i think
Explanation:
The SI unit of electric current is the ampere, or amp, which is the flow of electric charge across a surface at the rate of one coulomb per second. The ampere (symbol: A) is an SI base unit Electric current is measured using a device called an ammeter.
To a flask, 15.0 mL of 1.25 M hydrofluoric acid is added. Then, 3.05 M NaOH is used to titrate the acid sample. Write the balanced net ionic equation for the acid-base reaction.
HF(aq) + OH^- → H2O(I) + F^-
Answer:
H^+(aq) + OH^-(aq) --------> H2O(l)
Explanation:
We must first obtain the molecular equation, the net ionic equation before we obtain the net ionic equation.
The molecular reaction equation is;
HF(aq) + NaOH(aq) -------> H2O(l) + NaF(aq)
The complete ionic equation is;
H^+(aq) + F^-(aq) + Na^+(aq) + OH^-(aq) --------> H2O(l) + Na^+(aq) + F^-(aq)
The net ionic equation is;
H^+(aq) + OH^-(aq) --------> H2O(l)
A student connects a battery to a wire and wraps the wire around an iron nail to produce an electromagnet. Which action
should the student take to increase the number of paper clips the electromagnet can pick up?
He should replace the iron nail with a plastic spoon.
He should add another battery.
He should decrease the current through the wire
He should reduce the number of turns
Answer:
He should add another battery.
Explanation:
An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire wound into a core of magnetic material usually an iron core. When an electric current-producing battery is connected to the wire, an electric current will begin to flow and the iron core will become magnetized. When the battery is disconnected, the iron core will lose its magnetism.
Electromagnets works based on the electromagnetic field which is a field force due to the interaction of the electric and magnetic fields. the force on the wire is proportional to the size of the current, the length and thickness of the iron core, as well as the number of turns of wire around the iron core.
Therefore, from the number of possible action given that the student can take in order to increase the magnetism of his electromagnet, adding another battery, thereby increasing the current will be the best way to increase the number of paper clips tat his electromagnet can pick up.
Answer:
they are correct he should add another battery trust me
Suppose you want to prepare a buffer with a pH of 4.59 using formic acid. What ratio of [sodium formate]/[formic acid) do you need to make this buffer? Formic acid has a K, of 1.8x10 4 Enter your answer to three significant figures.
Answer:
7.08
Explanation:
To solve this problem we'll use the Henderson-Hasselbach equation:
pH = pka + log[tex]\frac{[A^-]}{[HA]}[/tex]Where [tex]\frac{[A^-]}{[HA]}[/tex] is the ratio of [sodium formate]/[formic acid] and pka is equal to -log(Ka), meaning that:
pka = -log (1.8x10⁻⁴) = 3.74We input the data:
4.59 = 3.74 + log[tex]\frac{[A^-]}{[HA]}[/tex]And solve for [tex]\frac{[A^-]}{[HA]}[/tex]:
0.85 = log[tex]\frac{[A^-]}{[HA]}[/tex][tex]10^{(0.85)}[/tex]=[tex]\frac{[A^-]}{[HA]}[/tex][tex]\frac{[A^-]}{[HA]}[/tex] = 7.08The ratio of [sodium formate] to [formic acid] needed to make the buffer is 7.08
How to determine the pKaEquilibrium constant (Ka) = 1.8×10¯⁴pKa =?pKa = –Log Ka
pKa = –Log 1.8×10¯⁴
pKa = 3.74
How to determine the ratio of [sodium formate] to [formic acid]pH = 4.59pKa = 3.74Ratio of [sodium formate] to [formic acid] =?pH = pKa + Log[sodium formate]/[formic acid]
4.59 = 3.74 + Log[sodium formate]/[formic acid]
Collect like terms
4.59 – 3.74 = Log[sodium formate]/[formic acid]
0.85 = Log[sodium formate]/[formic acid]
Take the anti-log of 0.85
[sodium formate]/[formic acid] = anti-log 0.85
[sodium formate]/[formic acid] = 7.08
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Based on the vibrational difference you observed, state a hypothesis to explain why diatomic molecules in the air, such as oxygen and nitrogen, are not greenhouse gases while those with 3 or more atoms, such as methane, are?
Answer:
See explanation
Explanation:
The ability of a gas to function as a green house gas depends on its ability to absorb infra red rays. In turn, the absorption of infrared red rays depends on whether or not the molecule is IR active.
The triatomic molecules such as methane and water are IR active. Only IR active molecules can lead to green house effect.
Note that for a molecular vibrational mode to be IR active, the dipole moment of the molecule is changed as the vibration occurs .
a compound has a molar mass of 129 g/mol if its empirical formula is C2H5N then what is the molecular formula
Given :
A compound has a molar mass of 129 g/mol .
Empirical formula of compound is C₂H₅N .
To Find :
The molecular formula of the compound.
Solution :
Empirical mass of compound :
[tex]M_e = ( 2 \times 12 ) + ( 5 \times 1 ) + ( 1 \times 14 )\\\\M_e = 43\ gram/mol[/tex]
Now, n-factor is :
[tex]n = \dfrac{M}{M_e}\\\\n = \dfrac{129}{43}\\\\n = 3[/tex]
Multiplying each atom in the formula by 3 , we get :
Molecular Formula, C₆H₁₅N₃
The molecular formula of the compound is C₆H₁₅N₃.
Calculation:The Empirical mass of the compound is
[tex]= (2\times 12) + (5\times 1) + (1\times 14)\\\\[/tex]
= 43 gram/mol
Now n-factor should be
[tex]= 129 \div 43[/tex]
= 3
Now here we multiply every atom in the formula by 3 so it should be C₆H₁₅N₃
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How many TOTAL CELLS are created after a single cell goes through THREE COMPLETE CYCLES of mitosis?
Answer:
4 cells are made after 3 rounds of mitosis
Explanation:
Measurements show that the enthalpy of a mixture of gaseous reactants increases by 319kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that 92kJ of work is done on the mixture during the reaction. Calculate the change of energy of the gas mixture during the reaction in kJ.
Answer:
the change in energy of the gas mixture during the reaction is 227Kj
Explanation:
THIS IS THE COMPLETE QUESTION BELOW
Measurements show that the enthalpy of a mixture of gaseous reactants increases by 319kJ during a certain chemical reaction, which is carried out at a constant pressure. Furthermore, by carefully monitoring the volume change it is determined that -92kJ of work is done on the mixture during the reaction. Calculate the change of energy of the gas mixture during the reaction in kJ.
From thermodynamics
ΔE= q + w
Where w= workdone on the system or by the system
q= heat added or remove
ΔE= change in the internal energy
q=+ 319kJ ( absorbed heat is + ve
w= -92kJ
If we substitute the given values,
ΔE= 319 + (-92)= 227 Kj
With the increase in enthalpy and there is absorbed heat, hence the reaction is an endothermic reaction.
Why is it necessary to run TLC in a closed container and to have the interior vapor saturated with the solvent? What error is introduced into the determination of an Rf value if the top is left off of the developing chamber?
Answer:
See explanation
Explanation:
Rf value is known as retention factor.The retention factor of a particular material is the ratio of the distance the spot moved above the origin to the distance the solvent front moved above the origin(Harper College).
TLC is carried is out in a closed container and the interior is saturated with the solvent vapor in order to have a maximum resolution between components this prevents solvent from evaporating from the system.
Peradventure the solvent for the separation is partly or wholly lost due to an open container, the Rf value would be lower than the expected value.
Can someone help me real quick?
Im pretty sure its C
What would a student carrying out a titration use a to transfer 25 mL of sodium hydroxide into a conical flask?
a) conical flask
b) burette
c) measuring cylinder
d) pipette
Convection is said to occur in _______ , which includes liquids and gases.
Question 1 (0.25 points)
What is the name for the land area where all rain runs downhill to a certain point?
O watershed
O collection
O estuary
O ocean
In an ecosystem , watershed is the name for the land area where all rain runs downhill to a certain point.
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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Name 3 types of equations used to describe reactions in solutions?
Answer:
Types of Chemical Reactions
Synthesis reactions. Two or more reactants combine to make 1 new product. ...
Decomposition reactions. A single reactant breaks down to form 2 or more products. ...
Single-replacement reactions. A single element replaces a similar element of an adjacent reactant compound. ...
Double-replacement reactions. ...
Combustion reactions.
Explanation:
