The atom of element has 25 electrons and 30 neutrons write down its atomic number and mass number.
Answer:
Atomic number = 25 protons
Mass number = ( 25 + 30 ) = 55
Standardization of a Borax solution (Na2B4O7). You are given a 1.044 M solution of H2SO4. It takes 2.63 mL of this H2SO4 to reach the end point. Knowing it takes 1 H2SO4 to neutralize 2 Na2B4O7, what was the concentration of this Borax solution?
The question is incomplete, the complete question is:
Standardization of a Borax solution (Na2B4O7). A student titrates a 20.00 mL sample of an aqueous borax solution with 1.044 M H2SO4. It takes 2.63 mL of acid to reach the equivalence point. Knowing it takes 1 H2SO4 to neutralize 2 Na2B4O7, what was the concentration of this Borax solution?
Answer: The concentration of borax solution is 0.069 M.
Explanation:
To calculate the concentration of borax solution, the formula used is:
[tex]n_1C_1V_1=n_2C_2V_2[/tex] ....(1)
where,
[tex]n_1, C_1\text{ and }V_1[/tex] are the n-factor, concentration and volume of sulfuric acid
[tex]n_2,C_2\text{ and }V_2[/tex] are the n-factor, concentration and volume of borax solution.
We are given:
[tex]n_1=1\\C_1=1.044M\\V_1=2.63mL\\n_2=2\\C_2=?M\\V_2=20mL[/tex]
Putting values in equation 1, we get:
[tex]1\times 1.044\times 2.63=2\times C_2\times 20\\\\C_2=\frac{1\times 1.044\times 2.63}{2\times 20}\\\\C_2=0.069M[/tex]
Hence, the concentration of borax solution is 0.069 M.
A teacher brings in a cup of iced water and asks students to discuss if the system is exothermic or endothermic . Aida states the system is exothermic , while Alexander states the system is endothermic .
Answer:
C
Explanation:
In thermodynamics, a exothermic system looses heat to the surroundings while an endothermic system absorbs heat from the surroundings.
A system is a part the universe marked off by a specified boundary. The contents of the cup constitutes the system in this case.
The region of space outside the system is called the surroundings. Hence everything outside the cup constitutes the surroundings.
How does light demonstrate quantization?
A. The velocity of a light wave has a direction as well as speed.
B. The wavelength of light increases as the frequency decreases.
C. The frequency of light increases as energy increases.
D. The energy in light waves comes in units called photons.
Answer:
D. The energy in light waves comes in units called photons.
Explanation:
its known as quatum theory
Identify which of the following statements about the isotopes of an element is correct.
A. They have the same electron configuration.
B. They have the same mass number.
C. They have the same numbers of protons and neutrons in the nucleus.
D. They have more protons than neutrons.
Answer:
A
Explanation:
because B is wrong as it doesn't have the same mass number. C is wrong as it has different number of neutrons. D is wrong as it has more neutrons than protons.
A neutral atom has 37 electrons. How many protons does the
atom have?
a more than 37 protons
bless than 37 protons
C exactly 37 protons
d it is impossible to know without more information
Answer:
It's answer is c) exactly 37 protons
Answer:
C) , Exactly 37 protons.
Explanation:
Remember the electrons have a negative charge, so to make a atom with 37 electrons neutral, you will need the same amount of the opposite type. That means you need 37 protons.
What is the speed of a wave that has a frequency of 220 Hz and a wavelength
of 0.39 m?
A. 0.002 m/s
B. 564 m/s
C. 85.8 m/s
D. 0.01 m/s
Answer:
12d
Explanation:
What exacerbates the heat waves?
Answer:
A heatwave occurs when a system of high atmospheric pressure moves into an area and lasts two or more days.
Explanation:
In such a high-pressure system, air from upper levels of our atmosphere is pulled toward the ground, where it becomes compressed and increases in temperature.
What BEST describes these three molecules?
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Pls answer the below questions
What is Malleability
What is ductility
What is Sonorous
Answer:
Malleability describes the property of a metal's ability to be distorted below compression. It is a physical property of metals by which they can be hammered, shaped and rolled into a very thin sheet without rupturing. A malleable fabric could be planate by blow or rolling.
Explanation:
Ductility is the property of a solid, like a metal, to deform under a tensile stress (force). So if you pull on two ends of a metal wire or bar, and it “stretches” you have a ductile substance. Though I must caution that you don't confuse the definition of ductile to mean elastic. They are not synonyms. It is the opposite of brittle. When a ductile item breaks, it is after necking, where the diameter of the wire in question reduces as the length elongated. A brittle, or non-ductile material simple tears apart in a sharp and quick fashion with little to no visible necking taking place.
sonorous: producing sound (as when struck)
There are on average 43 g of sugar and 355 mL can of soda please calculate the molarity of sugar in the can of soda the molar mass of sugar is 342.2 g/mol
Explanation:
Given :
Amount of solute - sucrose (C12H22O11) = 41 g
Amount of solvent -soda = 355-mL
Molarity of the solution with respect to sucrose= ?
Molarity(M) is a unit of concentration measuring the number of moles of a solute per liter of solution. The SI unit of molarity is mol/L.
Formula to find the molarity of solution :
Molarity =
Amount of solvent is given in mL, let’s convert to L :
1 L = 1000 mL
Therefore, 355 mL in L will be :
= 0.355 L
We have the amount of solute in g, let’s calculate the number of moles first :
Number of moles (n) =
Molar mass of C12H22O11 = 342.29 g/mol.
Therefore, n =
= 0.119 moles.
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c) Current cannot flow
Reason: Because the switch is not closed.
Answer:
current can't flow
Explanation:
by the way of explanation it is open circuit in which the current flow whereas in closed circuit the current flow.
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Calculate the number of moles of NaOH in an aqueous solution of 36 cm3 of 0.1 mol dm−3.
PLSS EXPLAIN WHAT YOU DO I DONT GET IT
Answer: The number of moles of NaOH is 0.0036 moles
Explanation:
Molarity is defined as the amount of solute expressed in the number of moles present per liter of solution. The units of molarity are mol/L. The formula used to calculate molarity:
[tex]\text{Molarity of solution}=\frac{\text{Moles of solute}\times 1000}{ \text{Volume of solution (mL)}}[/tex] .....(1)
Given values:
Molarity of NaOH = [tex]0.1mol/dm^3=0.1mol/L[/tex] (Conversion factor: [tex]1L=1dm^3[/tex]
Volume of the solution = [tex]36cm^3=36 mL[/tex] (Conversion factor: [tex]1mL=1cm^3[/tex]
Putting values in equation 1, we get:
[tex]0.1=\frac{\text{Moles of NaOH}\times 1000}{36}\\\\\text{Moles of NaOH}=\frac{0.1\times 36}{1000}=0.0036mol[/tex]
Hence, the number of moles of NaOH is 0.0036 moles
the rate of diffusion of gas having molecules mass 4 times that ouch4 is 50 cc.the rate of diffusion of mithane is??
Answer: The rate of diffusion of methane is 100 cc.
Explanation:
Graham's law states that the rate of diffusion of a gas is inversely proportional to the square root of the molar mass of the gas. The equation for this follows:
[tex]\text{Rate}=\frac{1}{\sqrt{M}}[/tex] .....(1)
where M is the molar mass of the gas
We are given:
[tex]Rate_{X}=50cc[/tex]
[tex]M_{X}=4\times M_{CH_4}[/tex]
Since the molar mass of methane = 16 g/mol
Using equation 1:
[tex]\frac{Rate_{CH_4}}{Rate_{X}}=\sqrt{\frac{M_X}{M_{CH_4}}}[/tex]
Putting values in above equation, we get:
[tex]\frac{Rate_{CH_4}}{50cc}=\sqrt{\frac{(4\times 16)}{16}}\\\\Rate_{CH_4}=50\times \sqrt{4}\\\\Rate_{CH_4}=50times 2=100cc[/tex]
Hence, the rate of diffusion of methane is 100 cc.
List two possible steps where impurities may be gained, which would appear to be an increase in copper
yield (why you may get more than 100% of the copper back at the end). Be specific about the steps and
how they might add impurities.
Answer:
i) During washing
ii) During Measurement
Explanation:
The two possible steps are :
i) During washing : during the washing method the residue may be not completely dried out and this residue ( water) will add up to the final product ( copper yield ) and this kind of error is called human error.
ii) During measurement : If the weighing instrument is faulty there might be addition in value of the final copper yield which will see the final yield value > 100% . this error occurs when the initial value and final value is been weighed
why elements with more than 20 protons always have a more neutrons than protons?
Answer:
Elements that have atomic numbers from 20 to 83 are heavy elements, therefore the ratio is different. The ratio is 1.5:1, the reason for this difference is because of the repulsive force between protons: the stronger the repulsion force, the more neutrons are needed to stabilize the nuclei.
Helppppp plz ASAP DON’T GUESS
Explanation:
A B C D isme koyi ans hain doond lo
set goals and objectives for a company
Explanation:
Objectives and goals serve as a foundation for successful organizations since they establish the business's objective and aid in the identification of required measures. Goals are broad assertions of what you want to achieve, whereas goals are the precise stages or steps you need to take to get there.
give few property of PET
Answer:
Transparency to visible light and microwaves. Very good resistance to ageing, wear and heat. Lightweight, impact and shatter resistant. Good gas and moisture barrier properties
Explanation:
Answer:
Your Welcome! :)
Explanation:
What are the Characteristics of Polyethylene terephthalate (PETE or PET)?
Chemical Resistance: PET does not react with water or food which is one of the reasons it is used for consumable packaging.
Strength to Weight Ratio: PET is very strong for its lightweight.
Shatterproof: PET will not break or fracture.
How many grams are in 36.2 moles of Iron (I) fluoride?
Answer:
4084.808 grams (SigFigs: 4085 grams)
Explanation:
The molar mass of Iron fluoride is 112.84 g/mol.
To calculate the mass, multiply the molar mass by the number of moles.
36.2 mol * 112.84 g/mol = 4084.808 g
Convert to Sigfigs (if necessary):
4085 g
Answer:
The person above is correct
Explanation:
Which fundamental force(s) can act over very long distances?
A. Gravity and electrostatic force
B. Strong nuclear force and weak nuclear force
C. Gravity only
D. Electrostatic force and strong nuclear force
Answer:
C. Gravity only
Explanation:
When a catalyst is added to a chemical reaction it provides a new reaction pathway that results in a different
Answer: That results in a different ALTERNATE pathway which has a LOWER ACTIVATION ENERGY.
Explanation:
There are many factors that affects a chemical reaction, these include'
--> surface area
--> concentration,
--> temperature,
--> pressure and
--> presence of CATALYST.
A CATALYST is defined as the substance that has the ability to alter the rate of a chemical reaction. Many reaction very slowly when left alone, but become faster when other substances are added. Such substances that merely alter the rate of reactions but do not take part in the reactions are called CATALYSTS.
Activation energy is defined as the energy barrier that must be overcome before a reaction takes place. A catalyst is able to increase the rate of a chemical reaction by decreasing the activation energy of the chemical system.
A catalyst provides an ALTERNATE PATHWAY for the reaction that has a LOWER ACTIVATION ENERGY. When activation energy is lower, more reactant particles have enough energy to react, so the reaction occurs faster.
What is the function of the rough
ER?
A. build proteins
B. modify and repackage proteins
C. contains enzymes
A. build proteins
Explanation:
The endoplasmic reticulum can either be smooth or rough, and in general its function is to produce proteins for the rest of the cell to function. The rough endoplasmic reticulum has on it ribosomes, which are small, round organelles whose function it is to make those proteins
How many mL of 0.013 M potassium hydroxide are required to reach the equivalence point in the titration of 75 mL 0.166 M hydrocyanic acid?
Answer:
957.7mL
Explanation:
Using the formula below;
CaVa = CbVb
Where;
Ca = concentration of acid (M)
Va = volume of acid (mL)
Cb = concentration of base (M)
Vb = volume of base (mL)
According to the information provided in this question:
Ca = 0.166 M
Cb = 0.013 M
Va = 75mL
Vb = ?
Using CaVa = CbVb
0.166 × 75 = 0.013 × Vb
12.45 = 0.013Vb
Vb =12.45/0.013
Vb = 957.7mL
What is the value of the quantum number n for a spin-up electron in a 2p orbital?
A. +2
B. -1/2
C. +1
D. +1/2
Answer:
+1/2
Explanation:
spin up is always +1/2
-. You have 100 grams of methane. How many moles do you have?
Answer:
6.25mol
Explanation:
Using the following formula;
Mole = mass ÷ molar mass
According to this question, there are 100 grams of methane (CH4)
Molar Mass of methane (CH4) = 12 + 1(4)
= 12 + 4
= 16g/mol
mole = 100/16
mole = 6.25moles
Therefore, there are 6.25moles of methane in 100g
Some foods undergo sterilization in order to kill bacteria living in and on the
food. What type of radiation is used in sterilization to kill bacteria?
A. Gamma
B. Alpha
C. Beta
D. Fission
Answer:
A: Gamma
Gamma rays have enough energy to kill bacteria
Given the reaction:
Sn2+ (aq) + 2Fe3+ (aq) → Sn4+ (aq) + 2Fe2+ (aq)
The oxidizing agent in this reaction is?
A Sn2+
B Fe3+
C Sn4+
D Fe2+
tolong saya jawab yahhh
(i) Liang - liang stoma lebih banyak di bahagian bawah daun berbanding di bahagian atas permukaan daun.
(ii) Struktur X berfungsi mangawal pembukaan dan penutupan liang stoma
Jason combines the two intermediate steps shown. 2 equations. First: upper N subscript 2 (g) plus upper O subscript 2 (g) right arrow 2 upper N upper O (g). Second: 2 upper N upper O (g) plus upper O subscript 2 (g) right arrow 2 upper N upper O subscript 2 (g). Which best describes what Jason should do with the oxygen molecules?
Answer:
The molecules of oxygen should be placed as reactants in the equation.
Explanation:
1: N₂ + O₂ → 2NO
2: 2NO + O₂ → 2NO₂
complete reaction:
N₂ + 2O₂ → 2NO₂
In both intermediate equations' oxygen is used as reactant because the end product is the product of the combination of nitrogen and oxygen. So in the complete or overall reaction, oxygen should also be placed as reactant.We can not place oxygen at the side of products neither we can cancel it because, products can only be obtained at the end of the reaction but according to the equations' oxygen is not the end product of the reaction. But the addition into the reaction (Eq. 2) to make the new product.
Also, we can not cancel it because to cancel out molecules of oxygen should be present at the both sides with same amount in the stoichiometric equation.
Hence, in a balanced chemical equation, oxygen should be written as a reactant by using the correct number of moles.
