If I have 2.500 grams of magnesium how many moles of magnesium do I have?
Answer:
0.1029(rounded to sig figs)
Explanation:
convert from grams to moles
Amount in grams/molar mass of substance
Molar mass of Mg=24.305
So, 2.500/24.305=0.1028594939
Rounded to 0.1029
A chemist needs to know the mass of a sample of to significant digits. He puts the sample on a digital scale. This is what the scale shows:
0
0
0
7
6
.
3
g
If this measurement is precise enough for the chemist, round it to significant digits.
Otherwise, press the "No solution" button.
What type of reaction is displayed below?
HCI + NAOH → NaCl + H20
Answer:
neutralization reaction
Explanation:
This reaction involve an acid (HCl) reacting with a base (NaOH), producing a salt (NaCl) and water. Therefore it's a neutralization reaction
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When different atoms join together, they are called a compound. Compounds are made of molecules (so molecules could be an alternate answer, but not all molecules are compounds)
Answer:
it is compound
Explanation:
Two or more elements combined into one substance through a chemical reaction, such as water, form a chemical compound. All compounds are substances, but not all substances are compounds.
The particle on a ring is a useful model for the motion of electrons around the porphine ring, the conjugated macrocycle that forms the structural basis of the heme group and the chlorophylls. We may treat the group as a circular ring of radius 440 pm, with 22 electrons in the conjugation system moving along the perimeter of the ring. In the ground state of the molecules each state is occupied by two electrons.
A) Calculate the energy and angular momentum of an electron in the highest occupied level.
B) Calculate the frequency of radiation that can induce a transition between the highest occupied and lowest unoccupied levels.
Answer:
Explanation:
The formula for determining the energy of state [tex]m_l[/tex] can be computed by using the formula:
[tex]Em_i = \dfrac{m_1^2h^2}{2I}[/tex]
Also, the momentum is:
[tex]l_2 = m_i h[/tex]
There are 22 electrons with two electrons in each of the lowest II energy levels so that the highest occupied states are [tex]m_1 = \pm 5[/tex]
The moment of inertia of an electron on a ring of radius 440 ppm is:
[tex]I = mR^2 \\ \\ = 9.109 \times 10^{31} \ kg (440 \times 10^{-12}) ^2 \\ \\ = 1.76 \times 10^{-49} \ kgm^2[/tex]
[tex]E_{\pm 5 } = \dfrac{25h^2}{2I} \\ \\ = \mathbf{7.89 \times 10^{-19} \ J}[/tex]
The angular momentum is:
[tex]l_2 = \pm 5h \\ \\ = \pm 5 \tiems ( 1.05457 \times 10^{-34} \ Js)[/tex]
[tex]= \mathbf{5.275 \times 10^{-34} \ Js}[/tex]
B) Let's recall that:
The lowest occupied energy level is [tex]m_1 = \pm 6[/tex] which implies that the energy [tex]E_{\pm 6}= 1.14 \times 10^{-18} \ J[/tex]
Thus;
[tex]\Delta E = E_{\pm 6} - E_{\pm 5} \\ \\ = 1.14 \times 10^{-18 \ J} - 0.79 \times 10^{-18} \ J \\ \\ = 0.35 \times 10^{-18} \ J \\ \\ 0.35 \times 10^{-18} \ J = hv \\ \\ 0.35 \times 10^{-18} \ J = h \dfrac{c}{\lambda}[/tex]
Hence, the radiation which would induce a transition that relates to the wavelength of about 570nm, a wavelength of visible light.
NEEED HELP NOW
A new drug has been released to the public and is popular among
consumers. It is effective in relieving high blood pressure. However, it has
altered some patients' personalities. Which stage of the engineering process
may address this negative side effect?
A. Evaluating test results
B. Looking for improvements
C. Screening
D. Testing
Answer: looking for improvements
Explanation:
Answer:
B. Looking for improvements
Explanation:
took the quiz and got in right on a pex
HELP I WILL GIVE YOU BRAINLIST!!!
Pick one substance (ex: water and table salt) and compare two of the atoms connected to each other (ex: H and O, Na and Cl) and answer the following questions for each pair:
1)Are they close or far away from each other on the periodic table?
Do they have similar atomic radii?
2)Do they have a large or small difference in ionization energy? What about for electron affinity?
How many molecules are in 13.2 L F2
Answer:
3.55 x 10^23 molecules F2
Explanation:
molecules = moles x avogadro number
1 mole of gas occupies 22.4 L
moles of F2 = 13.2/22.4= 0.589 moles
moles F2 = 0.589 x 6.022 x 10^23 = 3.55 x 10^23 molecules F2
A cook prepares a solution for boiling by adding 12.5 g of NaCl to a pot holding 0.750 L of water. At what temperature should the solution in the pot boil? {Normal boiling point is 100oC and Kb = 0.512 oC kg/mol and density of water is 1 kg/L}
Thanks!!
Answer:A cook prepare a solution for boiling by adding 12.5g of NaCl to a pot holding 0.750L of water. ... 12.5g of NaCl to a pot holding 0.750L of water. At what temperature should the solution in the not boil? *. 1 ... Which of the following is best suited to be counted by moles a. roses in a store b. books in a library c.
Explanation:
3 Zn + 2 MnF3 ---------> 2 Mn + 3 ZnF2
Using the reaction above, calculate how many grams of manganese (Mn) are produced in this reaction when 8.5 moles of Zinc (Zn) are used as a reactant?
Answer:I’ll ask my teacher
Explanation:
Explain how you would separate a mixture of soil. pebbles, and iron filings.
Explanation:
if they aren't in a solvent, then you magnetize first, to remove the iron fillings, secondly, you can sieve to separate the sand and pebbles
Separate the pebbles by either straining them out or pulling each one out separately with tweezers or your fingertips.
What is separation?To separate their soil mixes using the tools you have supplied, ask the groups to develop a plan. They might consider using forceps to separate the soil, shaking it between two tumblers, placing it in a water-filled tumbler, or pouring it through air. Invite student groups to present their ideas.
Pbbles - Separate the pebbles by either straining them out or pulling each one out separately with tweezers or your fingertips. As a strainer, a colander or a section of window screen works well. Iron fillings Using a magnet, it is simple to remove the tiny iron filings from the mixture.
Therefore, separate the pebbles by either straining them out or pulling each one out separately with tweezers or your fingertips.
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Please please help me please please help please please help me please please help please please help me please
Answer:
A
I honestly think it's A, but I could be wrong. It might be B, but I don't think so.
How does the respiratory system function?
Answer:
The lungs and respiratory system allow oxygen in the air to be taken into the body, while also letting the body get rid of carbon dioxide in the air breathed out. When you breathe in, the diaphragm moves downward toward the abdomen, and the rib muscles pull the ribs upward and outward.
Explanation:
The lungs and respiratory system allow oxygen in the air to be taken into the body, while also letting the body get rid of carbon dioxide in the air breathed out. When you breathe in, the diaphragm moves downward toward the abdomen, and the rib muscles pull the ribs upward and outward.
Counting Atoms in Compound 8cl2o
An aqueous solution contains
32.7% KCI (weight weight %)
How many grams of KCl are
contained in 100 g of this solution
Molar Mass
KCE: 74.55 g/mol
H20 18.016 g/mol
Answer:
32.7
Explanation:
I just did it and got it right
Which best describes the process that occurs when liquid water becomes
ice?
Answer:
Freezing
Explanation:
When a liquid goes to a solid, this process is called freezing.
Answer:
The water molecules get condensed and form a solid matter called ice. This process is called Condensation.
Indicate which of these statements about catalysts are true. 1) In an equilibrium process, a catalyst increases the rate of the forward reaction, but leaves the rate of the reverse reaction unchanged. 2) A catalyst is not consumed in the course of a reaction. 3) A catalyst must be carefully chosen to shift the equilibrium toward products.
Answer:
2) A catalyst is not consumed in the course of a reaction.
Explanation:
A catalyst is a substance which increases the rate of chemical reaction and remains chemically unchanged at the end of the reaction. The addition of a catalyst increases the rate of both reversible and irreversible reactions. including reversible reactions involving a final equilibrium state. In reversible reactions, catalysts speed up the time for equilibrium to be attained.
Considering the given statements about catalysts:
1) In an equilibrium process, a catalyst increases the rate of the forward reaction, but leaves the rate of the reverse reaction unchanged.
False: A catalyst increases both the forward and reverse reaction rates equally, thereby allowing the system to reach equilibrium faster.
2) A catalyst is not consumed in the course of a reaction.
True: Catalysts are substances that increase reaction rates without being consumed in the reaction.
3) A catalyst must be carefully chosen to shift the equilibrium toward products.
False: A catalyst does not affect the extent or position equilibrium of a reaction since a catalyst speeds up both the forward and back reactions by equal amounts , rather it helps a reaction achieve equilibrium faster.
The concentration of a benzene solution prepared by mixing 12.0 g
C6H6 with 38.0 g CCl4 is __________ molal
Answer: The concentration of a benzene solution is 4.05 molal
Explanation:
Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.
[tex]Molality=\frac{n\times 1000}{W_s}[/tex]
where,
n = moles of solute
[tex]W_s[/tex] = weight of solvent in g
moles of [tex]C_6H_6[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{12.0g}{78g/mol}=0.154mol[/tex]
Now put all the given values in the formula of molality, we get
[tex]molality=\frac{0.154\times 1000}{38.0g}=4.05[/tex]
Therefore, the concentration of a benzene solution is 4.05 molal
What % of original U238 remains after three half lives?
1-50
2-25
3-12.5
4-6.25
Answer:
12.5
Explanation:
After three half-lives, one eighth (1/2 x 1/2 x 1/2) of the uranium-238 will remain. One-eighth equals 12.5%
what does the word interact
Lift
Fly
Discuss
Work with
Answer:
The answer would be work with.
Explanation:
Because, if we know what the word interact means then we can look for a word similar to interact. hope this makes sense <3.
Help help help !!!!!!
Answer:
3. 116.5 V
4. 119.6 V
Explanation:
3. Determination of the voltage.
Resistance (R) = 25 Ω
Current (I) = 4.66 A
Voltage (V) =?
V = IR
V = 4.66 × 25
V = 116.5 V
Thus, the voltage is 116.5 V
4. Determination of the voltage.
Current (I) = 9.80 A
Resistance (R) = 12.2 Ω
Voltage (V) =?
V = IR
V = 9.80 × 12.2
V = 119.6 V
Thus, the voltage is 119.6 V
help someone i need this
15POINTS I NEED HELP WITH THIS QUESTION PLEASE!
Answer:
12.76 g
Explanation:
Step 1: Write the balanced equation
4 Fes + 7 O₂ ⇒ 2 Fe₂O₃ + 4 SO₂
Step 2: Calculate the moles corresponding to 11.15 g of O₂
The molar mass of O₂ is 32.00 g/mol.
11.15 g × 1 mol/32.00 g = 0.3484 mol
Step 3: Calculate the moles of SO₂ produced from 0.3484 moles of O₂
The molar ratio of O₂ to SO₂ is 7:4.
0.3484 mol O₂ × 4 mol SO₂/7 mol O₂ = 0.1991 mol SO₂
Step 4: Calculate the mass corresponding to 0.1991 moles of SO₂
The molar mass of SO₂ is 64.07 g/mol.
0.1991 mol × 64.07 g/mol = 12.76 g
Hydrogen has an oxidation number of +1 in all compounds excepts when it binds with metals and has an oxidation state of -1.
Answer:
See explanation
Explanation:
In the periodic table, hydrogen is placed in group 1 for convenience. Hydrogen is not a metal, however, its common oxidation state is +1. It easily forms a univalent positive ion just like group 1 elements.
So, when hydrogen is combined with strongly electropositive metals such as sodium, lithium, etc, hydrogen accepts one electron and exhibits an oxidation state of -1 in those compounds.
Such compounds in which hydrogen is combined with strongly electropositive metals to give a binary compound is called a hydride.
How are fossil fuels formed from geologic processes?
Answer:
Explanation:
Fossil fuels are hydrocarbons, namely, petroleum , coal and natural gas, formed from buried combustible geologic deposits of organic and natural materials. They are created from decayed animals and plants that convert into coal, crude oil or heavy oil due to constant exposure to pressure and heart in the earth’s crust.
The compounds that make up plankton and plants convert into fossil fuels. Plankton decomposes into natural gas and oil, while plants become coal. Nowadays, humans extract these resources through coal mining and the drilling of oil.
What are fossil fuel ?The term fossil fuel is defined as they are made from decomposing plants and animals. An example of a fossil fuel is coal, as well as oil and natural gas.
Because they were generated from the petrified, buried remains of plants and animals that once lived millions of years ago, coal, crude oil, and natural gas are all referred to as fossil fuels.
Thus, The remains of these animals underwent a transformation into what we now know as fossil fuels over millions of years at great pressure and high temperature.
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describe which process in the water cycle the water in each picture will go through next will go through next.
Answer:
water vapour I guess I the answer of your question
A group of students is setting up a test to see whether earthworms, like those shown in the photo, prefer rough or smooth surfaces
Answer:
they like smooth
Explanation:
Which one of the following represents an acceptable set of quantum numbers for an electron in an atom? (arranged as n, l, ml, and ms)
2, 2, -1, -1/2
3, 3, 3, 1/2
3, 3, 3, -1/2
5, 4,- 5, 1/2
2, 1, 0, 1/2
What is the product of the equation shown?
2 Na + S203
A. Na S203
B. NaS40
C. Na2S205
D. Na2S2O3
Answer:
D
Explanation:
balancing of chemical equations
Can we change a planet’s gravity?
Answer:
No, We cannot change a gravitational field directly. Gravity is due or caused by the energy in objects with mass. ... Either way, once a particle, it is an object thus a source of gravitational potential.
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there are no current practical outer space applications of artificial gravity for humans due to concerns about the size and cost of a spacecraft necessary to produce a useful centripetal force comparable to the gravitational field strength on Earth.