Answer:
Explanation:
For pH of a buffer solution , the equation is
pH = pKa + log [ A⁻ ] / [ HA ]
Putting the values
7 = - log 56 x 10⁻¹⁰ + log [ NH₃ ] / [ NH₄⁺]
7 = 10 - log 56 + log [ NH₃ ] / [ NH₄⁺]
- 3 + 1.748 = log [ NH₃ ] / [ NH₄⁺]
log [ NH₃ ] / [ NH₄⁺] = - 1.25
[ NH₃ ] / [ NH₄⁺] = [tex]10^{-1.25}[/tex]
Required ratio = [tex]10^{-1.25}[/tex]
2 )
In the formation of NH₄⁺ , generally HCl acid is required . A little bit of excess HCl will change the pH required . So , this mixture is a poor choice for getting pH 7 for a buffer solution .
what is the mass number of an atom or ion with one proton, two neutrons, and one electron?
Answer:
3
Explanation:
mass no.=protons+neutrons
mass no.=1+2=3
Read the scenario, then answer the questions. A 2 kg ball is thrown upward with a velocity of 15 m/s. What is the kinetic energy of the ball as it is being thrown? J What is the potential energy of the ball when it gets to its maximum height just before falling back to the ground? J
Answer:
225 for both answers
Explanation:
The only reason i know this is because i got it wrong. 225
Answer:
225J on both of the questions.
What is the scientific method and how does it work?
Answer:
scientists use the scientific method to collect measurable, empirical evidence in an experiment related to a hypothesis. The process of the scientific method involves making conjectures.
Rotation about a carbon-carbon double bond does not readily occur because: __________.1) the overlap of the p orbitals of the carbon-carbon π bond would be lost2) the double bond is much shorter and therefore more difficult to rotate3) the overlap of the sp2 orbitals of the carbon-carbon σ bond would be lost4) the double bond is much stronger and therefore more difficult to rotate
Answer:
1) The overlap of the p orbitals of the carbon-carbon π bond would be lost
Explanation:
Unlike simple bonds, a double bond can not rotate, since it is not possible to twist the ends of the molecule without breaking the π bond.
In the structure of but-2-ene present in the attachment, we can see the two isomers, cis and trans. These isomers cannot be interconverted by rotation around the carbon-carbon double bond without breaking the π bond.
How you could use the scientific method to learn whether water really does take longer to boil if you are watching it.
Answer:
Please find the detailed explanation below
Explanation:
A scientific method is a sequence of steps that is used to solve a problem. Every scientific method begins with a problem that needs to be solved.
Hence, in order to determine whether water really does take longer to boil if you are watching it, we employ the steps involved in a scientific method.
1) Ask a question/Make observation: This must initiate the process. The observation/question made here is that DOES WATER TAKE LONGER TIME TO BOIL WHEN WATCHED?
2. Formulating hypothesis; an hypothesis is a testable prediction of a possible solution to the stated problem. In this case, an hypothesis could read: IF water is watched while boiling, THEN it will take a longer time to boil. A hypothesis must be tested for it to be proved or disproved.
3. Test hypothesis: The formulated hypothesis is tested via conducting an experiment. The set up of the experiment can involve one group where water is boiled while watching it and another where water is boiled without watching. The former group is called Experimental group, while the latter group is called Control group. The time it takes for each group of water to boil will be recorded.
The independent variable (manipulated variable) will be the WATCHING, while the dependent variable (tested/responding variable) will be the TIME IT TAKES FOR WATER TO BOIL
4. Analyse the data; the data refers to the recorded time for each group of water. This will be analysed and compared.
5. Make conclusion; the conclusion depends on the result, which is the recorded time for each group of boiled water. Based on the result, the hypothesis can either be rejected or accepted. For example, if the control group boils faster than the experimental group, our hypothesis will be accepted but if otherwise, the hypothesis will be rejected.
Therefore, via the scientific method, it can be determined if it really takes longer time for water to boil while watched.
When a piece of metal mass of 54.52 g is dropped into a graduated cylinder containing 23.44 mL of water, the water level rises to 28.85 mL. What is the density of the metal? Answer in units of g/cm3
Answer:
Density = 10.01 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]Density = \frac{mass}{volume} [/tex]From the question
mass of metal = 54.52 g
Volume of metal = new volume - original volume of water in the cylinder
That's
new volume = 28.85 mL
original volume of water = 23.44 mL
Volume of metal
= 28.85 - 23.44 = 5.41 mL
Next we convert the volume from mL to cm³
1 mL = 1 cm³
5.41 mL = 5.41 cm³
Substitute the values into the above formula and solve
That's
[tex]Density = \frac{54.52}{5 .41} \\ = 10.07763[/tex]We have the final answer as
Density = 10.01 g/cm³Hope this helps you
Compare and contrast how are predation and parasitism similar how do they differ
I need help on these two questions please!!!
Answer:
5. A. Shape and volume
6. A. Solid to liquid
7. C. Gas
Mike rides his motorcycle North at an average velocity of 20 meters/second for 500 seconds, how far did he ride?
Answer:
10000
Explanation:
Answer:10,000 meters
Explanation:20x500=10,000
What phase would this substance be in at a pressure of 1.25atm and a temperature of 700C
Answer:
i dont have much detail, but im pretty sure it would be at a boil/vaporizing phase.
Convert 75 mL of water to gallons (show work)
Answer:
0.01981 gallons.
Explanation:
In this problem, we need to convert 75 mL of water to gallons.
We know that, 1 gallon = 3785.41 mL
To convert 75 mL to gallons, we must use to the unitary method such that,
1 mL = (1/3785.41) gallon
So,
[tex]75\ mL=75\times \dfrac{1}{3785.41}\\\\=0.01981\ \text{gallons}[/tex]
So, there are 0.01981 gallons in 75 mL of water.
Which phrase describes an irregular galaxy?
What is kinetic energy? Give an example please.
Kinetic energy is moving energy or the energy of motion.
If an object is moving like a rock rolling down
a mountain, we say the rock has kinetic energy.
Question 2
1 pts
Which value below correctly expresses the answer to this calculation:
(Reminder: consider sig figs)
310 x 0.00189 x 42.0 =
Consider an ion with the symbol X2+ formed from a representative element. (5.2, 5.3)a. What is the group number of the element?b. What is the electron-dot symbol of the element?c. If X is in Period 3, what is the element?d. What is the formula of the compound formed from X and the nitride ion?
Answer:
a) the element belongs to group 2
b) see image attached
c) Magnesium
d) X3N2
Explanation:
Any ion with the formula X^2+ was derived from group 2 elements. The group two element found in period 3 is magnesium alone.
Since the nitride ion has a valency of -3 and X^2+ has a valency of +2 , then a compound formed between X^2+ and the nitride ion will have the formula X3N2.
a. The group number of the element can be determined by knowing the charge of the ion. In the ion X2+ has a charge of 2+. Since representative elements typically form ions with charges equal to their group numbers, we can conclude that the group number of the element X is 2.
b. The electron-dot symbol, also known as Lewis dot symbol, represents the valence electrons of an element. Since X is a representative element in Group 2, it has two valence electrons.
c. If X is in Period 3, it could be one of the elements from Group 2 in that period. The most likely element would be Magnesium (Mg), as it is the representative element in Group 2 of Period 3.
d. The nitride ion has a charge of 3-. To form a neutral compound, the charges of X and the nitride ion must balance out. Since X has a charge of 2+ and the nitride ion has a charge of 3-, we need two X ions to balance the charge of three nitride ions. Therefore, the formula of the compound formed from X and the nitride ion is X3N2.
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Perform the following conversion: 6.1 × 103 K (the surface temperature of the Sun) to °F and °C. Pay attention to the number of significant figures in this problem. (Enter your answers in scientific notation.)
Answer:
[tex]\°C=5.8x10^3\°C[/tex]
[tex]\°F=1.1x10^4\°F[/tex]
Explanation:
Hello,
In this case, for the calculation of the temperature in degree Celsius we subtract 273.15 to the given temperature in kelvins:
[tex]\°C=6100-273.15\\\\\°C=5.8x10^3\°C[/tex]
Next, by applying the following equation we compute it in degree Fahrenheit:
[tex]\°F=(5.8x10^{3}*9/5) + 32\\\\\°F=1.1x10^4\°F[/tex]
Clearly, since the initial unit has two significant figures the computed units also show two significant figures.
Regards.
Someone pls help me I don’t know this one
Select the correct statement about thermochemical equations from the following: Select one:
a. The specific heat capacity of all substances involved in the chemical reaction are listed to the right of the balanced chemical equation.
b. Because the enthalpy change of the reaction depends on the states of matter of the substances, they must be shown for each substance in the equation.
c. Positive values for the enthalpy change of a reaction indicate that the reaction released energy.
d. If the chemical reaction is reversed, then the arithmetic sign of the change in enthalpy stays the same.
Answer:
Because the enthalpy change of the reaction depends on the states of matter of the substances, they must be shown for each substance in the equation.
Explanation:
The enthalpy of a substance depends on the particular state of matter in which it occurs.
Therefore, in a thermo chemical equation, all the states of matters for all the chemical species in the equation must be accurately written so that the thermo chemical equation can be meaningful.
The correct statement about thermochemical equations is the enthalpy
change of the reaction depends on the states of matter of the substances,
they must be shown for each substance in the equation.
Enthalpy is defined as the heat change that occurs in a reaction or the sum
of the internal energy present. It is associated with change in matter and is
dependent on the physical states of the reactants and products.
This is the reason why the physical states such as solid, liquid, gas etc have
to be shown in a thermochemical equation.
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Calculate the volume of a sample of mercury with a density of 14.6 g/mL and a mass of 1.00 g.
The answer is assumed to be in mL. Please include a numeric value only with significant figures
Answer:
hiiiiiiiijsiosoaplq
Which of the following correctly lists the compounds in order of decreasing acidity?
A) H2O > HCCH > NH3 > CH3CH3
B) HCCH > H2O > NH3 > CH3CH3
C) CH3CH3 > HCCH > NH3 > H2O
D) CH3CH3 > HCCH > H2O > NH3
E) H2O > NH3 > HCCH > CH3CH3
Answer:
A) H2O > HCCH > NH3 > CH3CH3
Explanation:
H2O is known as a neural compound which a pH close to 7.0. This however makes it more acidic due to it having the lowest pH when compared to the others in the option.
The other options however have their acidic strength as follows: HCCH > NH3 > CH3CH3. This explains why the pattern of decreasing acidic strength is H2O > HCCH > NH3 > CH3CH3
Calculate the millimoles of solute in 1.88 L of a 0.00713 M NaCN solution. millimoles:
Answer:
13.4 milimoles.
Explanation:
The following data were obtained from the question:
Volume = 1.88 L
Molarity = 0.00713 M
Millimoles of NaCN =?
Next, we shall determine the number of mole NaCN in the solution. This can be obtained as follow:
Molarity = mole /Volume
Volume = 1.88 L
Molarity = 0.00713 M
Mole of NaCN =?
Molarity = mole /Volume
0.00713 = moles of NaCN /1.88
Cross multiply
Mole of NaCN = 0.00713 × 1.88
Mole of NaCN = 0.0134 mole
Finally, we shall convert 0.0134 mole to Millimoles. This can be obtained as follow:
1 mole = 1000 millimoles
Therefore,
0.0134 mole = 0.0134 × 1000
0.0134 mole = 13.4 milimoles
Therefore, the millimoles of the solute, NaCN in the solution is 13.4 milimoles
An object has a mass of 295 lbs. Convert this into kilograms (show work) ((last question))
Explanation:
kg = Ibs/2.2046 (from internet)
kg = 295/2.2046
= 133.81 kg
Two substances, A and B, with the same melting point. How can you determine if they are the same without using any form of spectroscopy? Explain in detail.
Answer:
Simply carry out the mixed melting point procedure
1 here grind the two substances mix them
2.take note of the melting point of the mixture this is P
3 also get the original product from a different source okay this is Q
4.so I the melting point of P = Q then they represent a similar compound
5. But if melting point of P is not equal to Q then one of the compounds is P is acting as an impurity so they are not the same
The compound has been similar or not has been determined with the determination of the shift in the melting point of the mixture of the two compounds.
The melting point can be defined as the temperature of the substance when it has been converted from the solid state to the liquid state.
The two substances were found to have the same melting point. The compounds have been determined whether they are similar or not by the determination of the melting point of the combined mixtures.
The compounds A and B have been mixed together, and the melting point has been determined. The similar compounds in mixing will give the same melting point. While if the compounds are different, there has been a shift in the melting point of the mixture.
Thus, the compound has been similar or not has been determined with the determination of the shift in the melting point of the mixture of the two compounds.
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Please answer ASAP >_<
What does xylem do in a plant?
•transport food
•transport water
•prevent water loss
•perform photosynthesis
Answer:
The correct answer is B. Transport water.
Explanation:
I did this quiz. :)
Xylem transport water. Therefore, the correct option is option B among all the given options. The vascular tissue of plants called xylem.
What is xylem?The vascular tissue of plants called xylem transports water plus dissolving minerals from the roots towards the rest of the plant while also offering structural support. The tracheary components, a collection of specialized, water-conducting cells, make up xylem tissue.
All vascular plants, along with the seedless club mosses, fern, horsetails, all angiosperms (flowering plants), and gymnosperms, include xylem in addition to phloem (tissue that transports glucose from the leaves to the rest of the plant) (plants with seeds unenclosed in an ovary). Xylem transport water.
Therefore, the correct option is option B.
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All organisms need a place to live that provides
Answer:
Living Space get food or nutrients, water, and shelter. No matter where an organism lives, it must provide what it needs to survive.
Explanation:All organisms need a place to live, and store energy to take care of itself.
Given that O2 is paramagnetic and has a bond order of 2, and its highest occupied molecular orbital is antibonding, what would be the expected bond orders for O22- and O22
Answer:
Bond order of O22- = 1
Bond order of O22+ = 3
Explanation:
The bond order is given by;
1/2(number of bonding - number of anti bonding electrons).
In O22- , there are ten bonding and eight anti bonding electrons giving a bond order of 1 from; 1/2 (10 - 8) = 1
Similarly, for O22+ , we have ten bonding and four antibonding electrons, hence;
1/2 (10 - 4) = 3
A physical change is chemically the same after the experiment.
True
False
Answer: True
Explanation:
Does standard enthalpy use net ionic equations?a. Trueb. False
Answer:
True
Explanation:
In an ionic reaction, the net ionic equation is used to calculate the standard enthalpy of reaction.
Hence the standard enthalpy of any ionic reaction can be obtained by considering its balanced net ionic reaction equation, hence the answer above.
How many millimoles of Cr2O72- ions and K1+ ions are present in 483. mL of a 0.0750 M K2Cr2O7?1. mmolCr2O72-
2. mmol K1+
Answer:
72.45 mmol K⁺ and 36.225 mmol Cr₂O₇²⁻
Explanation:
It is possible to obtain millimoles of a substantce by the multiplication of molarity times milliliters of the solution.
In the solution that is 0.0750M K₂Cr₂O₇:
K⁺ = 0.0750M * 2 = 0.150M
Cr₂O₇²⁻ = 0.0750M
The millimoles of these ions are:
Millimoles K⁺:
483mL * 0.150M = 72.45 mmol K⁺
Millimoles Cr₂O₇²⁻:
483mL * 0.075M = 36.225 mmol Cr₂O₇²⁻
Can somebody help me please? it’s urgent
Answers:
See attached table
Explanation:
The isotope symbol will have the mass number and chemical symbol. The atomic number will be equal to the number of protons because the atomic number is the number of protons in an atom. The electrons will be equal to the protons because the atom is neutral. The neutrons can be found by subtracting the number of protons from the mass number. The mass number can be found by adding the protons and neutrons. It is also in the name of the isotope.