Round the following number to 4 significant figures... 11278.30 *
1 point
11280
1128
11278
78.30

Answers

Answer 1

Answer:

11280

Explanation:


Related Questions

For the reaction of Zn (s) with Cu(NO3)3 (aq), write the molecular, complete ionic and net ionic equations.

Answers

Answer:

Explanation:

Molecular reaction

Zn + Cu( NO₃ )₂ = Zn( NO₃ )₂ + Cu

Complete reaction

Zn + Cu⁺² + 2 NO₃⁻ =  2 Zn⁺² + 2 NO₃⁻ + Cu

net ionic reaction

Zn + Cu⁺² = Zn⁺² + Cu

Calculate the percentage by mass of lead in Pb(NO3)2. Calculate the percentage by mass of lead in Pb(NO3)2. 65.3 62.6 44.5 71.2 38.6

Answers

Answer:

62.6 %

Explanation:

Pb(NO₃)₂  = 207 + 124 = 331 gram

331 gram of lead nitrate contains 207 grams of lead

100 gram of lead nitrate contains

207 x 100 / 331  = 62.6 %

It can be deduced that percentage by mass of lead in Pb(NO₃)₂ is B. 62.6%.

How to calculate the percentage?

From the given information, Pb(NO₃)₂ = 207 + 124 = 331 grams.

Therefore, 331 gram of lead nitrate contains 207 grams of lead. It can be deduced that 100 gram of lead nitrate will contain:

= 207 x 100 / 331

= 62.6 %

In conclusion, the correct option is 62.6%.

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A hypothetical element consists of two isotopes of masses 69.95 amu and 71.95 amu with abundances of 25.7% and 74.3%, respectively. What is the average atomic mass of this element?

a. 71.95 amu
b 71.4 amu
c. 69.95 amu
d. 70.95 amu
e. 70.5 amu

Answers

Answer:

Option B. 71.4 amu

Explanation:

From the question given above, the following data were obtained:

Isotope A:

Mass of A = 69.95 amu

Abundance (A%) = 25.7%

Isotope B:

Mass of B = 71.95 amu

Abundance (B%) = 74.3%

Average atomic mass =..?

The average atomic mass of the element can be obtained as shown below:

Average atomic mass = [(Mass of A × A%)/100)] + [(Mass of B × B%)/100)]

= [(69.95 × 25.7)/100] + [(71.95 × 74.3)/100]

= 17.977 + 53.459

= 71.436 ≈ 71.4 amu

Therefore, the average atomic mass of the element is 71.4 amu

If the analysis of carbon in a molecule indicates sp hybridization, what must be the shape around the carbon

Answers

Answer:

The shape around the carbon is linear . Sp hybridisation generally tends to be linear.

Explanation:

The hybridization procedure includes blending of the valence s orbital with one of the valence p orbitals to yield equal sp hybrid orbitals which can be orientated in a linear geometry. The p orbital is one orbital that could keep up to 2 electrons. The sp set is equal orbitals that factor 180° from every other.

Hence , the answer is linear shape around the carbon.

Calculate the formula mass for HFO2

Answers

Answer:

The molar mass is 210.49 g/mol

Explanation:

WILL GIVE BRAINLIEST AND LOTS OF POINTS
I rlly need help its due tomorrow

Alma is planning on joining the track team this year. In preparation for the season, Alma decides she wants to start running on her own to get in shape.

The next day, Alma decides to work on short sprints instead of long-distance running. Explain how Alma’s body cells would obtain energy differently when she sprints than when she runs long distances. When would her body’s cells make energy more efficiently? Why?

Answers

Alma is using ATC-PC which is a quick fuel source. Which is the first energy used in short and quick uses of energy.  While it gives the max energy at first, after about 10 seconds it runs out. Which then short term energy starts. Which uses carbs as energy. This gets to max energy after a little bit and after a few minutes, it starts to run out. Then long term energy kicks in. This uses oxygen to provide energy, while it lasts for a long time, it takes time to reach max energy.  This can also fail if your respiratory system or cardiovascular system can't provide enough oxygen.

B. For the following questions, use the reaction SO3(g) SO2(g) + O2(g), with ΔH = 98.4 kJ/mol and ΔS = 0.09564 kJ/(mol·K). (8 points)


i. Draw a possible potential energy diagram of the reaction. Label the enthalpy of the reaction. (2 points)

(A picture from online will do I just need some sort of drawing)
THANK YOU VERY MUCH I REALLY NEED THIS!!

Answers

Answer:

A).

ΔH is positive, Therefore reaction is endothermic

B).

ΔG = ΔH - T∙ΔS

= 98.4 kJ/mol - 300K ∙ 0.09564 kJ/molK

= 69.7 kJ/mol

C).

ΔG is positive, Therefore reaction is non-spontaneous

Explanation:

look i know that its not a drawing but its the best that i can do with what i have. i hope this helps!

What question might a scientist ask about a cuttlefish?
A. Why are cuttlefish so ugly?
B. Do cuttlefish taste good?
C. Is it wrong to eat cuttlefish?
D. What do cuttlefish have in common?

Answers

Answer:

D. What do cuttlefish have in common?

Explanation:

A P E X 2021 :)

The  question that a scientist might ask about cuttlefish is, "What do cuttlefish have in common that is present in Option D?" as the cuttlefish is an invertebrate and a member of the phylum Mollusca.

What are the general characteristics of the phylum Mollusca?

The phylum Mollusca includes the octopus, cuttlefish, and other aquatic animals with soft bodies that can easily blend in with the background in order to capture prey or avoid the predator, and they have other adaptations too, such as the digestive system and other organs, as they are organ-level organisms. They have the outer hard shell that is present in the snail, and they can reproduce sexually and show larval forms of development.

Hence, the question that a scientist might ask about cuttlefish is, "What do cuttlefish have in common that is present in Option D?" as the cuttlefish is an invertebrate and a member of the phylum Mollusca.

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What do the blue and red lines indicate?
A cold front is moving to the north and west before a warm front moves through.
A cold front is moving to the south and east before a warm front moves through.
A warm front is moving to the north and east before a cold front moves through.
A warm front is moving to the south and west before a cold front moves through.
WILL GIVE BRAINLIEST!

Answers

Answer:

this the one i needed help on pleasee sb help meh out

Explanation:

Answer:

A cold front is moving to the north and west before a warm front moves through.

Explanation:

PLEASE HELP!!!
Students combine several chemicals and record the observations in their science notebooks. A list of the observed results is given here. • Production of a gas (bubbles) • Phase change (solid to liquid) • A precipitate forms • Change in shape • Crystals dissolving • Heat produced How many of the observations are evidence that a new substance was formed? *
1 point
3
4
5
6

Answers

Answer:

3

Explanation:

I have indeed already took the quizzes my friend

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Movement of earths tectonic plates appears to be caused by

Answers

Answer: The force that causes most of the plate movement is thermal convection, where heat from the Earth's interior causes currents of hot rising magma and cooler sinking magma to flow, moving the plates of the crust along with them. ... In ridge push and slab pull, gravity is acting on the plate to cause the movement

One method for removing hydrogen sulfide impurities from natural gas is by its reaction with oxygen at high temperatures to form sulfur and water vapor. After balancing the following equation, determine the coefficient in front of the reactant O2. H2S(g) + O2(g) → S8(l) + H2O(g) Group of answer choices

Answers

Answer:

4

Explanation:

H2S(g) + O2(g) → S8(l) + H2O(g)

Upon balancing the equation;

8H2S(g) + 4O2(g) → S8(l) + 8H2O(g)

The coefficient of O2 in the reaction above is 4.

please help!! chemistry question

Answers

Answer:

9

Explanation:

Answer:

9

because i studied this

1. How are chemical bonds formed? *

Answers

Answer:   Bonds form when atoms share or transfer valence electrons. Valence electrons are the electrons in the outer energy level of an atom that may be involved in chemical interactions. Valence electrons are the basis of all chemical bonds.

Explanation: Due to atoms and science ;)

Answer:

throught transferring or sharing an electron

Explanation:

a p e x :)))


Which of the following sets of quantum numbers (n, l, m, ms) is possible for a 5f electron?
0 4,3,0,-
O 5,3,0,-
O 5, 3, +4,- 42
O 5, 2, 0, - 42
O 5,3,0,0

Answers

The possible quantum numbers for 5f are :

n = 5l =f = 3ml = -3,-2,-1,0,1,2,3ms = +1/2 or -1/2  Further explanation

Each orbital in an atom consists of 4 quantum numbers  

n is the principal quantum number ---> describes the size of the orbitals  

l is the angular momentum / azimuthal quantum number -> describes the shape of the orbitals.  

ml, the magnetic quantum number -> describes the orientation of orbitals in space  

ms, the electron-spin quantum number ---> describes the spin of electrons  

Value of n: positive integer  

value of l: s = 0, p = 1, d = 2, f = 3, ... (n-1)  

ml value: between -l to + l  

ms value: +1/2 or -1/2  

So the possible quantum numbers for 5f are :

n = 5l =f = 3ml = -3,-2,-1,0,1,2,3ms = +1/2 or -1/2  

Because the answer choices are not very clear, please see the composition I have described above

Aqueous hydrochloric acid will react with solid sodium hydroxide to produce aqueous sodium chloride and liquid water . Suppose 30.3 g of hydrochloric acid is mixed with 25. g of sodium hydroxide. Calculate the minimum mass of hydrochloric acid that could be left over by the chemical reaction. Be sure your answer has the correct number of significant digits.

Answers

Answer:

[tex]m_{HCl}^{leftover}=7.50g[/tex]

Explanation:

Hello.

In this case, since the undergoing chemical reaction is:

[tex]HCl+NaOH\rightarrow NaCl+H_2O[/tex]

In order to identify the limiting reactant, we compute the available moles of sodium hydroxide (molar mass = 40 g/mol) and the moles of hydrochloric acid consumed by those moles via their 1:1 mole ratio considering the chemical reaction:

[tex]n_{HCl}=25.0gNaOH*\frac{1molNaOH}{40gNaOH} *\frac{1molHCl}{1molNaOH} =0.625molHCl[/tex]

Next, since the molar mass of hydrochloric acid is 36.46 g/mol, we compute the mass of that reactant that is actually consumed:

[tex]m_{HCl}=0.625molHCl*\frac{36.46gHCl}{1molHCl}=22.8gHCl[/tex]

In such a way, the leftover of HCl is:

[tex]m_{HCl}^{leftover}=30.3g-22.8g\\\\m_{HCl}^{leftover}=7.50g[/tex]

Best regards!

Find the density of an object that has a volume of 2.3 x 10^2 and a mass of
3.5 x 10^3. *

Answers

Answer:

[tex]\frac{250}{23}[/tex]

Step-by-step explanation:

[tex]10^{2} = 100[/tex]  2.3 × 100 = 230[tex]10^{3} = 1000[/tex]  3.5 × 1000 = 3500[tex]D = \frac{m}{v}[/tex]  [tex]D = \frac{3500}{230}[/tex]  3500 ÷ 230 = [tex]\frac{250}{23}[/tex]  

I hope this helps!

when the tempature of the enviroment changes, the body tempature of a reptile

Answers

The reptile's body temperature rises when the external temperature rises. When the temperature drops, so does his body temperature. If a reptile feels cold because the external temperatures have made his blood cold, he'll lie in the sun to warm up.

hope this helps!!

Which of the following questions about the flu is a scientific question?
A. Is a flu shot effective in preventing the flu?
B. Is public fear of the flu out of control?
C. Is the benefit of drugs for the flu higher than the cost?
D. Who should receive a flu shot if there is not enough flu vaccine for
everyone?

Answers

The correct answer is A. This is because they are asking if the flu shot is necessary and effective to work to prevent the flu. We automatically know B is not the answer because the question is very unnecessary and does not sound like it could be a scientific question. C can’t be it because it’s talking about if the shot is beneficial because of the cost. It also can’t be D because it definitely does not make sense for there not to be a vaccine available for the people who need it for the flu. In this case the best option would be A.

Answer:

A is the correct answer

Explanation:

I need help ASAP please .................. You have a mixture of water, alcohol, and iron. Tell me, how would you separate them from each other?

Answers

Do u still need help

How many grams of Cu(OH)2 will precipitate when excess KOH solution is added to 76.0 mL of 0.764 M Cu(NO3)2 solution

Answers

Answer:

5.66g of Cu(OH)2 can be produced

Explanation:

Cu(NO3)2 reacts with KOH, as follows:

Cu(NO3)2 + 2KOH → Cu(OH)2 + 2KNO3

76.0mL of 0.764M Cu(NO3)2 are, in moles:

0.0760L * (0.764mol / L) = 0.0581 moles Cu(NO3)2

As 1 mole of Cu(NO3)2 produce 1 mole of Cu(OH)2, the moles of Cu(OH)2 produced are 0.0581 moles Cu(OH)2.

Molar mass of Cu(OH)2 is 97.561g/mol. In 0.0581 moles there are:

0.0581 moles Cu(OH) * (97.561g / mol) =

5.66g of Cu(OH)2 can be produced

The interaction of water droplets in rain with carbon dioxide that is naturally present in the atmosphere causes rain water to be slightly acidic because CO2 is an acidic anhydride. As a result, pure clean rain has a pH of about 5.7. What are the hydrogen ion and hydroxide ion concentration in this rain water

Answers

Answer:

Explanation:

 pH = 5.7

- log [ H⁺ ] = 5.7

[ H⁻ ] = 10⁻⁵°⁷ M

= 2 x 10⁻⁶ M

[ H⁺ ] x [ OH⁻ ] = 10⁻¹⁴

2  x 10⁻⁶ x [ OH⁻ ] = 10⁻¹⁴

[ OH⁻ ] = .5 x 10⁻⁸ M

= 5 x 10⁻⁹ M

) Chromate/Dichromate Equilibrium. Yellow chromate ion reacts with hydrogen ion to form (by condensation and loss of H2O) the orange dichromate ion:

Answers

Answer:

Explanation:

The Chromite ore is used for the production of Chromate/dichromate formation.

[tex]4FeCr2O4 + 8Na2CrO4+7O2 \\[/tex] →[tex]8NaCrO4 +2Fe2O3 +8CO2\\yellow[/tex]

so[tex]Na2CrO4[/tex] is called Chromite ore which is of yellow color.

[tex]Na2CrO4 +2H^+[/tex] → [tex]Na2CrO4 +2Na^+ +H2O[/tex]

                                [tex]Orange[/tex]

so when sodium chromate is reacted with hydrogen ion it forms sodium dichromate which is of orange color

Now

[tex]Na2Cr2O7+2KCl[/tex]→[tex]K2Cr2O7 + NaCl[/tex]

The chromate and dichromate are interconvertible in aqueous solution depending upon the PH of solution

Acid medium: [tex]Cr2O4^2-[/tex] [tex]2H^+[/tex]→[tex]Cr2O7^2-[/tex][tex]+H2O[/tex]

Base:[tex]Cr2O7^2- +2OH^-[/tex]→  [tex]CrO4^2- +H2O[/tex]

Hence Chromate and dichromate are interconvertible and hold and equilibrium.

In his 1859 book On the Origin of Species, Charles Darwin stated
that modern organisms have evolved from common ancestors
through he process of
d
O adaptation
O evolution
diversification
O natural selection
pls help

Answers

natural selection

Explanation:

The hydrolysis of sucrose (C12H22O11) into glucose and fructose in acidic water has a rate constant of 1.8×10−4s−1 at 25 ∘C. Assuming the reaction is first order in sucrose, determine the mass of sucrose that is hydrolyzed when 2.45 L of a 0.170 M sucrose solution is allowed to react for 195 min.

Answers

Answer:

Explanation:

k = 1.8 x 10⁻⁴ s⁻¹

no of moles initially = 2.45 x .17 = .4165 moles

initial moles a = .4165

k = (1 / t ) ln a / ( a - x )

a is initial moles , x is moles reacted .

a is initial moles , x is moles reacted .

time t = 195 min = 11700 s

1.8 x 10⁻⁴ = 1 / 11700 x ln .4165 /( .4165 - x )

2.106 = ln .4165 /( .4165 - x )

.4165 /( .4165 - x ) = e²°¹⁰⁶ = 8.215

.4165 = 3.42 - 8.215 x

8.215 x = 3.0035

x = .3656

moles of sucrose hydrolysed = .3656 moles.

What else is produced during the replacement reaction of magnesium and hydrochloric acid? I Will Give Brainiest To who ever gets right

Mg + 2HCl H2 + ________

MgCl2
Mg2Cl2
Mg2Cl
MgCl

Answers

Explanation:

In the reaction of magnesium with hydrochloric acid magnesium chloride and hydrogen gas is formed.

Equation -

Mg + 2HCl → MgCl₂ + H₂↑

Therefore,

Option A is correct ✔.

Answer:

Its A

Explanation: Just took the Pre-Unit test

A student mixed 25 grams of salt into 1,000 grams of water.
What is the mass of the mixture?
A. 975 grams
B. 1,000 grams
C. 1,025 grams
D. 2,500 grams

Answers

The answer is C. 1025 grams

The two main postulates that was given by Antoine Lavoisier are, oxygen play an important role in combustion and the other is mass of reaction is always conserved. Therefore, the mass of the mixture is 1025g. the correct option is option C.

What is law of conservation of mass?

According to Law of conservation of mass, mass can neither be created nor be destroyed. Mass can only be transformed from one form to another. The law of conservation of mass was given by Antoine Lavoisier. Every reaction in nature follow the law given by Antoine Lavoisier that is mass is always conserved.

mass of salt+ mass of water=mass of solution

mass of salt =25 grams

mass of water=1,000 grams

substituting the given values, we get

25 grams+ 1,000 grams =mass of solution

mass of solution=1025g

Therefore, the mass of the mixture is 1025g. the correct option is option C.

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Ammonium perchlorate is the solid rocket fuel used by the U.S. Space Shuttle. It reacts with itself to produce nitrogen gas , chlorine gas , oxygen gas , water , and a great deal of energy. What mass of oxygen gas is produced by the reaction of of ammonium perchlorate

Answers

Answer:

2.9 g

Explanation:

The computation of the mass of oxygen gas produced is shown below:

As we know that

[tex]2NH_4ClO_4 \rightarrow N_2 + Cl_2 + 2O_2 + 4H_2O[/tex]

Now

The [tex]NH_4ClO_4[/tex] presented in 9.6g = 9.6 g/117.49 g/mol  

And, the mole ratio between the [tex]NH_4ClO_4 : H_2O[/tex] is 1 : 2

The moles of [tex]H_2O[/tex] produced is 2 × 9.6 g/117.49 g/mol

So,

Mass of H2O produced is

= 18.015 g/mol × 2 × 9.6 g/117.49 g/mol

= 2.94 g

- On a test, Helena is defining energy. Which must she include in order to get her answer marked correct?
○making objects more compact
O the ability to do work
O carrying through matter and space
O the bonds of atoms ​

Answers

Answer: Option 2, The ability to do work.

Explanation: Edge

Energy can be defined as:

B. the ability to do work, It can of many forms.

What is Energy?

Energy is the capacity of an item to take care of business. It might exist in potential, motor, warm, electrical, substance, atomic, or other different structures. As per the work-energy hypothesis, the work done is put away in the energy of the body.

Thus, option B is correct.

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An aqueous solution contains 0.22 M ammonium iodide. One liter of this solution could be converted into a buffer by the addition of:

Answers

Answer:

The addition of NH₃⁺

Explanation:

A buffer is an aqueous mixture of a weak acid and its conjugate base or vice versa.

In ammonium iodide, NH₄I, the ions in solution are ammonium ion, NH₄⁺ and iodide ion, I⁻.

The iodide ion is the conjugate base of the HI, a STRONG ACID, that means the addition of HI in solution wouldn't produce a buffer.

And, NH₄⁺ is the conjugate acid of the NH₃, a WEAK BASE, that means the addition of NH₃ to the solution will produce a buffer: The mixture of a weak base, NH₃ and its conjugate acid, NH₄⁺

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