Answer:
MgBr
NaCl
Explanation:
What is the mass number of an isotope with an atomic number of 57 and that has 69 neutrons?
Answer:
mass number=126
Explanation:
57+69=126
A hydrogen atom initially in its ground state absorbs a photon with a wavelength of 97.25 nm. To which energy level is it excited
This question involves the concept of excitation energy.
The energy level to which the atom is excited is "4".
What is excitation energy?The excitation energy of an atom is defined as the energy required by the atom to get excited from one energy level to some upper energy level. Mathematically, it can be given by the following formula:
[tex]E=E_o(\frac{1}{n_i^2}-\frac{1}{n_f^2})[/tex]
where,
E = excitation energy = [tex]\frac{hc}{\lambda} = \frac{(6.63\ x\ 10^{-34}\ J.s)(3\ x\ 10^8\ m/s)}{9.725\ x\ 10^{-8}\ m}=2.04\ x\ 10^{-18}\ J[/tex]
E (in eV) = [tex](2.04\ x\ 10^{-18}\ J)(\frac{1\ eV}{1.6\ x\ 10^{-19}\ J})[/tex] = 12.78 eV
h = plank's constant = 6.63 x 10⁻³⁴ J>s
c = speed of light = 3 x 10⁸ m/s
λ = wavelength = 97.25 nm = 9.725 x 10⁻⁸ m
E₀ = energy of hydrogen atom in ground state = 13.6 eV
[tex]n_i[/tex] = initial orbit = 1
[tex]n_f[/tex] = final orbit = ?
Therefore,
[tex]12.78\ eV=13.6\ eV(\frac{1}{1^2}-\frac{1}{n_f^2})\\\\\frac{12.78\ eV}{13.6\ eV}=1-\frac{1}{n_f^2}\\\\\frac{1}{n_f^2}=1-0.94\\\\n_f^2=\frac{1}{0.06}\\\\n_f=\sqrt{16.67}\\n_f = 4[/tex]
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Guided Practice
Old-fashioned windmills are not aerogenerators because
Answer:
What is the main problem with windmills?
Image result for Guided Practice Old-fashioned windmills are not aerogenerators because
As with all energy supply options, wind energy can have adverse environmental impacts, including the potential to reduce, fragment, or degrade habitat for wildlife, fish, and plants. Furthermore, spinning turbine blades can pose a threat to flying wildlife like birds and bats.
Why are the windmills not moving?
Why do the turbines not spin at times? The most common reason that turbines stop spinning is because the wind is not blowing fast enough. Most wind turbines need a sustained wind speed of 9 MPH or higher to operate. Technicians will also stop turbines to perform routine maintenance or repairs.
Diethyl malonate reacts with propyl bromide in a three‑step reaction sequence. Identify the product that is formed. The highlighted carbons should correspond to the carbons from diethyl malonate
The product that is formed is shown in the figure , Option A is the correct answer , and the highlighted carbons shown corresponds to the carbons from diethyl malonate.
What is a Chemical Reaction ?
Chemical reaction, a process in which one or more substances, the reactants, are converted to one or more different substances, the products.
Substances are either chemical elements or compounds.
A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.
Chemical reactions are an integral part of technology, of culture, and indeed of life itself.
The product that is formed is shown in the figure , Option A is the correct answer , and the highlighted carbons shown corresponds to the carbons from diethyl malonate.
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How much mass would a sample of magnetite, a magnetic stone, with a volume of 8 cm^3 and a density of 5 g/cm^3 have?
Ionization, radical and valency electron
Answer:
Ionization, in chemistry and physics, any process by which electrically neutral atoms or molecules are converted to electrically charged atoms or molecules (ions).radical, also called Free Radical, in chemistry, molecule that contains at least one unpaired electron. For neutral atoms, the number of valence electrons is equal to the atom's main group number.What is the chemical formula of polypropylene (in text, no pictures)?
Answer:
(C3H6)n
it is made up of carbon and hydrogen atoms.
A solution of the ionic salt caso3 would have a ______ ph.
(acidic, basic, or neutral)
A solution of the ionic salt CaSO₃ would have an acidic pH.
What is pH?
This is referred to power of hydrogen and it measures the degree of acidity or alkalinity of a substance.
CaSO₃ which is referred to as calcium sulfite or calcium salt is formed through the reaction below and has a pH of 6 thereby making it an acidic salt.
SO₂ + CaCO₃ → CaSO₃ + CO₂
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Answer:
Basic
Explanation:
acellus
In reaction 1, 12g of reactants were converted to products in 30 seconds. In reaction 2, 200g of reactants were converted to products in 8 minutes. Which reaction happened at the faster rate?
Answer:
Reaction 2
Explanation:
12/30=0.4g/sec
200/(8*60)=0.41667g/sec
Determine the specific heat of a metal that has a mass of 34.57 g that absorbs 678 J of heat and is heated from 25.0 °C to 55.0 °C.
Answer: [tex]0.654 \text{ J/g} \cdot ^{\circ}\text{C}}[/tex]
Explanation:
[tex]678=(34.57)(c)(55.0-25.0)\\\\c=\frac{678}{34.57(55.0-25.0)} \approx \boxed{0.654 \text{ J/g} \cdot ^{\circ}\text{C}}}[/tex]
Why is science boring
Answer:
cuz what we are shown in school often fails to foster curiosity in us.
Explanation:
Explanation:
because it have many laws, theory, reaction and many more which is enough to make a student depressed
How does increased air temperatures affect salinity of the oceans and the great
ocean conveyor belt?
1. increased air temperatures decreases the salinity of the ocean since more ice is
melting adding more freshwater to the oceans, therefore slowing down the great
ocean conveyor belt.
2. increased air temperatures decreases the salinity of the ocean since more ice is
melting adding more freshwater to the oceans, therefore speeding up the great ocean
conveyor belt.
3. increased air temperatures increases the salinity of the ocean since more water is
evaporating into the atmosphere, therefore slowing down the great ocean conveyor
belt.
4. increased air temperatures increases the salinity of the ocean since more water is
evaporating into the atmosphere, therefore speeding up the great ocean conveyor
belt.
Increased air temperatures decrease the salinity of the ocean since more ice is melting adding more fresh water to the oceans, therefore slowing down the great ocean conveyor belt.
What is an ocean conveyor belt?Ocean conveyor belt system in which water moves between the cold depths and warm surface in oceans throughout the world.
Increases in temperatures of surrounding entities like ice and an increase in precipitation adds fresh water into the sea, which lower salinity. Seawater with lower salinity is lighter in density and won't sink as much as denser water.
As the seawater gets saltier, its density increases, and it starts to sink. Surface water is pulled in to replace the sinking water, which in turn eventually becomes cold and salty enough to sink. This initiates the deep-ocean currents driving the global conveyer belt.
Hence, option A is correct.
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what is an example of taking action or doing service in the cement industry
Answer:
mining of clay limestone and then heated to a certain temperature of 1450⁰ in a cement kiln
Antoine lavoisier is credited with the discovery of the law of conservation of mass. the law states that in a chemical reaction, matter is not created or destroyed but preserved. which equation correctly models this law?
h2 + cl2 ---> 2hcl
h2 + cl2 ---> hcl
h + cl ---> 2hcl
2h2 + cl2 ---> 2hcl2
The Antoine's law means that the amount of substance before reaction must be equal the amount of substance after reaction
The equation h2 + cl2 ---> 2hcl correctly models this law.
What is the molarity of 1. 5 liters of an aqueous solution that contains 52 grams of lithium fluoride.
Answer:
1.3 M
Explanation:
The formula mass of lithium fluoride is 7+19=26 g/mol. This means that in 52 grams of LiF, there is 2 moles.
Molarity = (moles of solute)/(liters of solution), so the answer is 2/1.5 = 1.3 M
What kind of music might you expect from a group that called themselves "The Entropics"?
Answer:
See explanation.
Explanation:
Heavy metal or something else that is heavily disordered. Would still sound better than cardi b.
Choose all that apply for raft spiders.
question 9 options:
raft spider's legs have a waxy surface that repels water
raft spiders sprint along submerged plants to catch underwater prey.
raft spider's light weight and large surface area allow it to walk on water.
raft spider's heavy weight and small surface area allow it to walk on water
Raft spider's light weight and large surface area allow it to walk on water.
What are raft spiders?Raft spiders are a specie of siders that can move on the surface of water. They are found around the north-western and central Europe.
The following apply to the raft spiders;
raft spider's legs have a waxy surface that repels waterraft spider's light weight and large surface area allow it to walk on water.Learn more about raft spiders:https://brainly.com/question/11416236?
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Jupiter revolves around the sun in a predictable pattern because
In a room there is a 100g block of aluminum and a container holding 200g of liquid water. In one instant the aluminum is 10 °C and the water is at 1 °C. At that instant, which object has more thermal energy? Show your work.
Answer:
Explanation:
Givens
The heat capacity for aluminum = 0.89 J/(oC*grams)
The heat capacity for water = 4.18
m water = 200 grams
t water = 1 degree C
t aluminum = 10 degrees C
Formula
Thermal energy = m * c * t
Solution
Water
Energy = m * c * t
Energy = 200 * 4.18 * 1
Energy = 836 Joules
Aluminum
Energy = mc t
Energy =100 * 0.89 * 10
Energy = 890
Answer Aluminum has the higher Thermal Energy
Note this is a very tricky question. Usually delta t is given in terms of a change in temperature or heat transfer. This question assumes the substance is at a constant temperature at a short time interval so delta t is a constant amount for that time interval. Be very careful when you think about this, because the laws of thermo dynamics begin to act almost immediately.
Calculate the energy required to produce 6.0 moles of Cl2O7 using the following reaction 2 Cl2 + 7 O2 + 130kcal -> 2 Cl207
Answer:
455 Kcal
Explanation:
2Cl2(g) + 7O2(g) + 130kcal → 2Cl2O7(g)
Rearranging we get,
2Cl2(g) + 7O2(g) → 2Cl2O7(g) Δ H = 130 kcal . mol⁻¹
So for per mol reaction will be as above.
In case of 7 mols of product, we need 7/2 mole ratio x 130 = 455 Kcal
Sodium hydroxide (NaOH) is a strong base that is very corrosive. What is the mass of 2.75 × 10-4 moles of NaOH?
3.24 x 10–3 g NaOH
1.10 x 10–2 g NaOH
6.10 x 10–2 g NaOH
6.50 x 10–2 g NaOH
The mass of 2.75 × [tex]10^{-4}[/tex]moles NaOH will be 1.1 x [tex]10^{-2}[/tex] grams
Mass/mole relationshipRecall that:
Mole = mass/molar mass.
Thus, mass = mole x molar mass.
In this case, the mole is 2.75 × [tex]10^{-4}[/tex] moles and the molar mass of NaOH is 40 g/mol.
Mass = 2.75 × [tex]10^{-4}[/tex]x 40 = 1.1 x [tex]10^{-2}[/tex] grams
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Answer:
Answer is option B or:
1.10 x 10–2 g NaOH
Explanation:
hope this helps! (edge)
A gas has a volume of 62.65 L at STP. At what temperature (in oC) would the volume of the gas be 78.31 L at a pressure of 612.0 mm Hg?
Answer:
1.788 C DEGREES
Explanation:
STP is 1 atm at 273.15 K
P1V1/T1 = P2V2/T2
(1)(62.65) / (273.15) = (612/760)(78.31)/T2
T2 = 274.93 K = 1.788 C
Suppose cobalt-60 undergoes a type of radioactive decay that does not
change the identity of the isotope. which type of decay did the isotope
undergo?
a. delta
b. gamma
c. alpha
d. beta
Gamma decay is a type of radioactive decay that does not change the identity of the isotope.
What is gamma decay?During gamma decay the nucleus emits radiation without actually changing its composition. In this type of decay only energy is released but the structure is same.
So we can conclude that gamma decay is a type of radioactive decay that does not change the identity of the isotope.
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Which of the following elements have the highest percentage in terms of frequency in the Earth's crust and human body, respectively? A. Nitrogen, Oxygen. B. Oxygen, Silicone. C. Carbon, Oxygen. D. Oxygen, Oxygen
Answer:
Oxygen is the most abundant element in the Earth's crust.
Explaination: It makes up 46% of the mass of the Earths crust.
Answer
The most abundant elements in the human body are oxygen, carbon and hydrogen. Oxygen makes up 65% of the body.
Can someone please help? This is super hard!!
Organic Compounds are named according to IUPAC Nomenclature technique.
The name for the first structure is 3-Bromo-2,4-dimethylhexane.
"International Union of Pure and Applied Chemistry "
Following are the names of given structures ;
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Need help with this chemistry question will reward with 50 points just please put the correct answer I'm very confused on it
Answer: 2Na3 (s)-> 2Na (s) +3N2 (g)
Explanation:
look at the keywords then balance equation
All the following ions have the same charge except Group of answer choices oxide. monohydrogen phosphate. peroxide. permanganate. oxalate.
All the given species have the same charge except peroxide.
Charges on ionsThe charge on monohydrogen phosphate is negative because of its formula, [tex][HPO4]^{2-}[/tex].The charge on permanganate is negative. The formula is [tex]MnO^-[/tex]The charge of oxide ([tex]O^{2-}[/tex]) is negative.The charge on peroxide is ( R−O−O−R) is neutral.The charge on oxalate, [tex]C2O4^{2-}[/tex], is negative.Thus, only peroxide is unique.
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1-3 gas stoichiometry! please help and put in steps in every problem. please help if u can
Answer:
um Im not sure what the heck that is
what is the different nobel gases that didnt have octet rule
The noble gas, Helium has only two electrons with the electronic configuration as 1s2. Hence, it does not have a complete octet. and thus, it doesn't follow the octet rule.
An octet is a set of eight. Atoms of each of the noble gases (except helium) have eight electrons in their highest occupied energy levels and the general electron configuration of ns2np6.
How many grams of glucose would be found in 1l of a 22% solution?
40 g glucose
Explanation:
I have to assume that you are asking about a 2% m/v solution ( Note that specifying 2% in isolation has no meaning )
2% m/v glucose solution is : 2 g glucose in 100 mL solution
Which is ( multiply by 10): 2% m/v = 20 g glucose in 1000 mL ( = 1.0 L) solution
And so 2%m/v = 40 g glucose in 2000 mL or 2.0 L solution
Answer: 40 g glucose.