Answer:
first and the last one hope this helps
Explanation:
How many moles are in 25.58 grams of H20?
Explanation:
1.42 Moles are there
A student pours a 10.0mL sample of a solution containing HC2H3O2(pKa=4.8) and NaC2H3O2 into a test tube. The student adds a few drops of bromocresol green to the test tube and observes a yellow color, which indicates that the pH of the solution is less than 3.8 . Based on this result, which of the following is true about the relative concentrations of HC2H3O2 and NaC2H3O2 in the original solution?
Answer:
[HC2H3O2] > NaC2H3O2
Explanation:
The concentration of [tex]\rm HC_2H_3O_2[/tex] has been higher than the concentration of [tex]\rm NaC_2H_3O_2[/tex].
The pKa has been defined as the acid constant that has been used for the determination of the strength of the acid. The higher the pKa value, the weaker the acid has been.
The [tex]\rm HC_2H_3O_2[/tex] has the pka value 4.8 depicting the solution has been a pH 4.8. With the addition of [tex]\rm NaC_2H_3O_2[/tex], the pH has been shifted towards the acidic condition, thus the Hydrogen concentration has been higher.
The change in the pH has been resulted in the reduction in the pH from the basic to acidic condition. Since the concentration of the [tex]\rm HC_2H_3O_2[/tex] has been higher than the [tex]\rm NaC_2H_3O_2[/tex] concentration, the pH has been shifted towards the more acidic condition.
Thus, the concentration of [tex]\rm HC_2H_3O_2[/tex] has been higher than the concentration of [tex]\rm NaC_2H_3O_2[/tex].
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the man is being warmed by?
radiation
convention
conduction
Answer:
Comvection
Explanation:
The movement causes the density to rise and therefore transfer more heat
You have 70 grams of aluminum. How many moles do you have
Answer:
70 moles is an Alluminium
6- A favorable condition for two elements to form an ionic bond is?
a- both should be electronegative
b- one should have low electron affinity and the other low ionization energy.
C- one should have high electron affinity and the other low ionization energy.
d- both should be highly electronegative
Answer: C- one should have high electron affinity and the other low ionization energy.
Explanation:
Ionization energy is the energy required to remove the electron from an isolated gaseous atom.
Electron affinity is the tendency of an isolated atom to attrcat the electrons towards itsellf.
An ionic bond is formed when an element completely transfers its valence electron to another element. The element which donates the electron is known as electropositive element or the metal and it can donate electron easily if it has low ionization energy.
The element which accepts the electrons is known as electronegative element or non metal and it can easily accept the electron if it has high electron affinity.
describe the difference between a physical and chemical change explain what happens during a checmical reaction
Explanation:
A physical change is a change that alters the physical properties of matter particularly the form and state.
In many cases the change is easily reversible. Examples are changes of state such as freezing, boiling, melting e.t.c
A chemical change is a change in which a new kind of matter is formed. It is always accompanied by energy changes which can either be evolution or absorption of heat or light or both.
The process is not easily reversible. Examples are combustion, rusting of iron, precipitation, e.t.c
During a chemical reaction, the reactants undergo a chemical change.
Jill graphs the speed of a model train that is travelling at a speed of 15 kilometers per hour. Which graph shows the speed of the model train?
Answer:c
Explanation:
If the wavelength of red light is 650 x 10^-9 meters (or 6.50x10^-7m) and the speed of light (c) is 3.00 x 10^8 m/s , what is its frequency in Hz?(1/sec = Hz) , and c = (wavelength x frequency)
Answer:
f = 4.6 × 10¹⁴ Hz
Explanation:
Given data:
Wavelength of light = 6.50x10^-7m
Speed of light = 3.00 x 10^8 m/s
Frequency of light = ?
Solution:
Formula:
Speed of radiation = frequency × wavelength
by putting values,
3×10⁸ m/s = f × 6.50x10^-7m
f = 3×10⁸ m/s / 6.50x10^-7m
f = 0.46 × 10¹⁵ s⁻¹
f = 0.46 × 10¹⁵ Hz
f = 4.6 × 10¹⁴ Hz
What is creating our Earth's Magnetic field?
1) Our Earth's iron liquid outer core rotating around the solid inner core
2) Our Earth having a stationary inner core
3) Our Earth having rocky center
4) All of the above
Answer:
1) Our Earth's iron liquid outer core rotating around the solid inner core
Explanation:
The earth's magnetic field or the geomagnetic field is produced as a result of the earth's iron liquid outer core rotating around the solid inner core.
This produces the earth's magnetic field.
The earth's core is made up of solid and liquid region. Only the densest elements are found within this region. So, the core is made up of metals which are mainly iron and nickel. The outer core is liquid or molten iron and the inner core is solid. The molten iron and nickel in the outer core moves around the inner core and generates the currents which induces a magnetic field round the earth.Weigh out the appropriate amount of HEPES sodium salt required to prepare 100 mL of a HEPES buffer that has pH 7.50 and is 90 mM in HEPES. FW for the HEPES sodium salt is 260.31. Transfer to a 150 mL beaker. Flowchart: Calculate the amount of HEPES sodium salt required to make the buffer.
Answer:
2.343 g of HEPES sodium salt is needed.
Explanation:
So, from the question above we have the following parameters which is going to help in solving this particular question.
The number of moles = 90mM, the pH = 7.50, FW for the HEPES sodium salt = 260.31, and the volume of HEPES sodium salt required = 100mL.
Therefore, the amount of HEPES sodium salt required to make the buffer = 260.31 × 9 × 0.001 = 2.343 grams of HEPES sodium salt is needed in 10mL.
A chemist prepares a solution of silver (I) perchlorate (AgCIO4) by measuring out 134.g of silver (I) perchlorate into a 50.ml volumetric flask and filling the flask to the mark with water. calculate the concentration in mol/L of the silver (I) perchlorate soluation
Answer:
13 M
Explanation:
Molar mass of AgCIO4 = 207 g/mol
Number of moles of AgCIO4= 134/207= 0.65 moles
Number of moles= concentration × volume
Concentration = number of moles/volume
Concentration = 0.65 × 1000/50 = 13 M
how many electrons does a covelent bond consist of?
Answer: 2 electrons
Explanation: Good luck! :D
Tim and Jose are moving furniture. Tim pushes a 150 kg sofa with 300N
force. As a result, Sofa’s acceleration was __________ according to Newton’s
Second Law of motion. (F = ma)
Answer:
a = 2m/s²
Explanation:
Given data:
Mass of sofa = 150 Kg
Force applied = 300 N
Acceleration = ?
Solution:
Formula:
F = ma
F = force
m = mass
a = acceleration
by putting values,
300 N = 150 Kg × a
a = 300 N /150 Kg
a = 300 Kg m/s² / 150 Kg ( N = Kgm/s²)
a = 2m/s²
aqueous hydrochloric acid HCl will react with solid sodium hydroxide NaOH to produce aqueous sodium chloride NaCl and liquid water H2O. Supposed 6.93 g of hydrochloric acid is mixed with 2.4 g of sodium hydroxide. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to 2 significant digits. g
Answer:
Explanation:
HCl + NaOH = NaCl + H₂O.
1 mole 1 mole 1 mole 1 mole
6.93 g of hydrochloric acid = 6.93 / 36.5 = .189 mole of HCl
2.4 g of NaOH = 2.4 / 40 = .06 mole of NaOH
NaOH is in short supply so it is the limiting reagent .
1 mole of NaOH reacts with 1 mole of HCl to give 1 mole of Water
.06 mole of NaOH will react with .06 mole of HCl to give .06 mole of water
Water formed = .06 mole
= .06 x 18 = 1.08 g
= 1.1 g
Thermodynamics and Q
How much energy is needed to heat 40.5g of water from 15.6°C to 73.0°C
Answer:
9717.246 J
Explanation:
From the question given above, the following data were obtained:
Mass (m) of water = 40.5 g
Initial temperature (T₁) = 15.6 °C
Final temperature (T₂) = 73 °C
Specific heat capacity (C) of water = 4.18 J/gºC
Heat (Q) =.?
Next, we shall determine the change in the temperature of water. This can be obtained as follow:
Initial temperature (T₁) = 15.6 °C
Final temperature (T₂) = 73 °C
Change in temperature (ΔT) =?
ΔT = T₂ – T₁
ΔT = 73 – 15.6
ΔT = 57.4 °C
Finally, we shall determine the heat energy required. This can be obtained as follow:
Mass (m) of water = 40.5 g
Specific heat capacity (C) of water = 4.18 J/gºC
Change in temperature (ΔT) = 57.4 °C
Heat (Q) =.?
Q = MCΔT
Q = 40.5 × 4.18 × 57.4
Q = 9717.246 J
Thus, the heat energy required is 9717.246 J
What is the formula for the ionic compound formed between sodium and oxygen?
Answer:
Na2O (the 2 is small the o is not a 0 but and OOh)
Explanation:
Hey there, The formula for the compound formed between sodium and oxygen will be Na2O
Though since sodium is a metal and oxygen is a nonmetal, Na2O is expected to be ionic.
What is an ionic compound?An ionic compound is a chemical compound made up of ions held together by electrostatic forces known as ionic bonding.
To determine an ionic compound's formula, first identify the cation and record its symbol and charge.
After that, identify the anion and record its symbol and charge. Finally, mix the two ions together to make an electrically neutral compound.
After two or more atoms lose or gain electrons to form an ion, an ionic bond can form.
Ionic bonds form when metals lose electrons and nonmetals gain electrons. Ions with opposite charges attract each other, forming an ionic bond.
The symbol for sodium is Na+, and the symbol for oxygen is O2. The resulting compound here in the given condition is Na2O.
Thus, this is the formula for the ionic compound formed between sodium and oxygen.
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How many moles are in 2.5 g of N2?
0.089 moles
KD 0.18 moles
1.3 moles
11 moles
Answer:
0.089
Explanation:
2.5/ 14= .178 then 0.178/ 2 again and you get 0.089
The moles of nitrogen in 2.5 grams of the compound is 0.089 moles. Thus option A is correct.
Moles can be calculated as the ratio of mass to molecular mass.
Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]
The mass of Nitrogen = 14 g/mol
The mass of diatomic nitrogen = 2 [tex]\times[/tex] mass of nitrogen
The mass of diatomic nitrogen = 2 [tex]\times[/tex] 14 g/mol
The mass of diatomic nitogen = 28 g/mol
The molecular weight of Nitrogen = 28g/mol
Given, the mass of Nitrogen = 2.5 g
Moles of nitrogen = [tex]\rm \dfrac{2.5}{28}[/tex]
Moles of Nitrogen = 0.089 moles.
The moles of nitrogen in 2.5 grams of the compound is 0.089 moles. Thus option A is correct.
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what is visibility ?
Answer:
Something or someone you can see invisibility is the opposite of something you cannot see or some thing you cannot see
Explanation:
A gas in a sealed container has a pressure of 100 kPa at a temperature of 27 C. If the pressure in the container is increased to 20 kPa, what is the new temperature?
Answer: 32.4 C
Explanation: Gay-Lussac's Law or Third Gas Law states that for a constant volume, the pressure is directly proportional to absolute temperature: P alpha T; also stated as P/T = K, where K is a constant, and similarly, P1/T1 = P2/T2 .
Here P1= 100 kPa, P2=120 kPa (If pressure increases by 20 kPA), T1=27 C [Given]
Hence, T2= (T1*P2)/P1 = (27*120)/100=32.4 C [C is degree in Celcius]
The new temperature of the gas in the container when the pressure increased by 20 KPa is 87 °C
Data obtained from the question Initial pressure (P₁) = 100 KPa Initial temperature (T₁) = 27 °C = 27 + 273 = 300 KNew pressure (P₂) = 120 KPa New temperature (T₂) =? How to determine the new temperatureThe new temperature of the gas can be obtained as follow:
P₁ / T₁ = P₂ / T₂
100 / 300 = 120 / T₂
Cross multiply
100 × T₂ = 300 × 120
Divide both side by 100
T₂ = (300 × 120) / 100
T₂ = 360 K
Subtract 273 to obtain answer in °C
T₂ = 360 – 273 K
T₂ = 87 °C
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[2071]State and explain Kohlrusch's law.
(2071]Why does the specific conductance decreases and equivalent conductance increase
with dilution of a solution of electrolyte?
ito unit How does it Vary with dilution?
1101
Dribbling a basketball harder into the floor makes it bounce higher is an example of what newton's law?
What type of weather typically results from a low pressure system?
I need help!!!!
Answer:
Storms and hurricanes can be formed with low pressure. It always results into unsettled weather.
Explanation:
Hope this helps!
The oldest known flower lived 120, million years ago. Is that a measured or exact number?
Answer:
measured
Explanation:
no way can they pin point exactly when something lived when its in the millions
BRAINLLEST! Boiling water for mac and cheese is a physical change. Give 2 pieces of evidence to support this claim
Answer:
In explanation.
Explanation:
Physical changes are generally changes in states of matter. So, the water going from liquid to gas is a phase change and therefore physical. (It's still water, just in a different form). Im not sure about the second piece of evidence though. Unless you are talking about the Mac and Cheese which in that case is also a physical change as the two ingredients cheese and macaroni stay the same when cooked just become softer and edible.
Think of 6 to 10 questions that ask participants how they keep (or kept) their
homes or businesses warm in cold weather and cool in hot weather. Your
questions may ask about the types of devices used, the sources of energy
used to run the devices, the effectiveness of the methods used, or effects on
the environment. worth 100 points!!
Answer:
One could be What kind of insulator do you use in the winter?
Explanation:
A nucleus with four protons has total positive charge
PLS HELP GIVING 100 PTS EASY SCIENCE HELP PLS
Answer:
B hope it helps
Explanation:
what can scientists learn from index fossils?
Answer:
dating and correlating the strata in which it is found
Explanation:
Answer:
The correct answer is A:The age of an unfamiliar layer of rock
Explanation:
I promise that I got it correct on A P E X <3
At what temperature a gas with volume 175 L at 15 oC and 760mmHg will occupy a volume of 198 L at a pressure 640mmHg?
Answer:
To calculate the pressure when temperature and volume has changed, we use the equation given by combined gas law. The equation follows:
\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}
T
1
P
1
V
1
=
T
2
P
2
V
2
where,
P_1,V_1\text{ and }T_1P
1
,V
1
and T
1
are the initial pressure, volume and temperature of the gas
P_2,V_2\text{ and }T_2P
2
,V
2
and T
2
are the final pressure, volume and temperature of the gas
We are given:
\begin{gathered}P_1=760mmHg\\V_1=175L\\T_1=15^oC=[15+273]K=288K\\P_2=640mmHg\\V_2=198L\\T_2=?K\end{gathered}
P
1
=760mmHg
V
1
=175L
T
1
=15
o
C=[15+273]K=288K
P
2
=640mmHg
V
2
=198L
T
2
=?K
Putting values in above equation, we get:
\begin{gathered}\frac{760mmHg\times 175L}{288K}=\frac{640mmHg\times 198L}{T_2}\\\\T_2=274K\end{gathered}
288K
760mmHg×175L
=
T
2
640mmHg×198L
T
2
=274K
Hence, the temperature when the volume and pressure has changed is 274 K
When fat comes in contact with sodium hydroxide, it produces soap and glycerin. Determine whether this is a physical change or a chemical change. Explain your
Answer: Chemical change
Explanation:
Physical change is a change where there is a change in size , shape etc and no new products are formed.
Chemical change is a change where there is a change in chemical composition as new products are formed.
Example: Formation of soap and glycerin from fat and sodium hydroxide is a chemical change as the chemical bonds are getting rearranged to form new products.
