A teacher moves a box of books weighting 25lbs a distance of 40ft. How much work has she done?

Answer:

Mass = 1188.13 g

Explanation:

Given data:

Mass of ZnO produced = ?

Moles of oxygen = 7.3 mol

Solution:

Chemical equation:

2Zn + O₂       →      2ZnO

Now we will compare the moles oxygen and and ZnO.

               O₂          ;        ZnO

                1            :           2

              7.3          :           2/1×7.3 = 14.6 mol

Mass of ZnO:

Mass = number of moles × molar mass

Mass = 14.6 mol × 81.38 g/mol

Mass = 1188.13 g

Answer:

The answer is 5,434.8 cm^3

The volume corresponding to 5,000 g of ice with a density of 0.92 g/mL is 5.4 × 10³ mL.

The density (ρ) is an intrinsic property of matter. It is equal to the quotient between the mass (m) and the volume (V). If we have 5,000 g of ice with a density of 0.92 g/mL, its volume is:

[tex]\rho = m/V\\V = m/\rho = 5,000 g/(0.92 g/mL) = 5.4 \times 10^{3} mL[/tex]

The volume corresponding to 5,000 g of ice with a density of 0.92 g/mL is 5.4 × 10³ mL.

You can learn more about density here: https://brainly.com/question/21667661

Answer:

B. an atom of oxygen o is destroyed in the reaction

Answer:

4.59 grams of hydrogen

Explanation:

57.010 g of ammonium phosphate * 1 mol / 149 g of ammonium phosphate * 12.0 g H * / 1 mol = 4.591409396.

But with sig figs, it rounds to 4.59.

So the final answer is 4.59 grams of hydrogen.

4.59g is the  mass of hydrogen in 57.010 grams of ammonium hydrogen phosphate. A mole is just a measuring scale.

A mole is just a measuring scale. In reality, it is one of the International System for Units' seven foundation units (SI). When already-existing units are insufficient, new ones are created. Using absolute amounts of atoms, molecules, or ions would be problematic as well since chemical reactions frequently occur at levels that use grams would be inappropriate.

A mole consists of precisely 6.022140761023 particles. The "particles" might be anything, from tiny things like electrons and atoms to enormous things like stars or elephants.

57.010 g of ammonium hydrogen phosphate× 1 mol / 149 g of ammonium phosphate ×12.0 g H× / 1 mol = 4.59g of hydrogen

Therefore, 4.59g is the  mass of hydrogen in 57.010 grams of ammonium hydrogen phosphate.

To know more about mole, here:

https://brainly.com/question/15209553

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Answer:

The answer is 20mph

Hope this helps!!!

This question was posted more than a month ago so... I guess I'll take the points if you don't mind?

Answer:

MOON

Explanation:

ITS PERIOD OF REVOLUTION IS EQUAL TO PERIOD OF ROTATION

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Answer:

285g of fluorine

Explanation:

To solve this problem we need to find the mass of Freon in grams. Then, with its molar mass we can find moles of freon and, as 1 mole of Freon, CCl₂F₂, contains 2 moles of fluorine, we can find moles of fluorine and its mass:

Mass Freon:

2.00lbs * (454g / 1lb) = 908g of Freon

Moles freon -Molar mass: 120.91g/mol- and moles of fluorine:

908g of Freon * (1mol / 120.91g) =

7.5 moles of freon * (2moles Fluorine / mole Freon): 15 moles of fluorine

Mass fluorine -Atomic mass: 19g/mol-:

15 moles F * (19g / mol) =

Answer:

13.749 x 10 -3 g

Explanation:

take the number of atoms that you have divided by Avogadro's number and then multiply by the molar mass of the element. :)

a. 661.23 m/s

b.  the rate of effusion of Ammonia = 4.5 faster than Silicon tetra bromide

Given

T = 25 + 273 = 298 K

Required

a. the gas speed

b. The rate of effusion comparison

Solution

a.

Average velocities of gases can be expressed as root-mean-square averages. (V rms)  

[tex]\large {\boxed {\bold {v_ {rms} = \sqrt {\dfrac {3RT} {Mm}}}}[/tex]

R = gas constant, T = temperature, Mm = molar mass of the gas particles  

From the question  

R = 8,314 J / mol K  

T = temperature  

Mm = molar mass, kg / mol  

Molar mass of Ammonia = 17 g/mol = 0.017 kg/mol

[tex]\tt v=\sqrt{\dfrac{3\times 8.314\times 298}{0.017} }=661.23~m/s[/tex]

b. the effusion rates of two gases = the square root of the inverse of their molar masses:  

[tex]\rm \dfrac{r_1}{r_2}=\sqrt{\dfrac{M_2}{M_1} }[/tex]

M₁ = molar mass Ammonia NH₃= 17

M₂ =  molar mass Silicon tetra bromide SiBr₄= 348

[tex]\rm \dfrac{r_1}{r_2}=\sqrt{\dfrac{348}{17} }=4.5[/tex]

the rate of effusion of Ammonia = 4.5 faster than Silicon tetra bromide

Answer:

Hi... Your answer is 10*50=500

Answer:

50x10 = 500 ; 500/5 = 100 watts

Explanation:

W/t /Force x Distance

the power is equal to the work done to the object divided by time.

Answer:

The rise and fall of the tides. Tides create a current in the oceans, which are strongest near the shore, and in bays and estuaries along the coast.

Winds drive currents that are at or near the ocean's surface.

Thermohaline circulation. This is a process driven by density differences in water due to temperature (thermo) and salinity variations in different parts of the ocean. Currents driven by thermohaline circulation occur at both deep and shallow ocean levels and move much slower than tidal or surface currents.

Currents affect the Earth's climate by driving warm water from the Equator and cold water from the poles around the Earth.

Explanation:

hope this helps

Answer:

C. The gas enters the cryosphere as ice sheets

Answer:

D

Explanation:

Answer:

the answer is the second one.

Answer:

Answers with detail given below.

Explanation:

1) NaBr + KF    →       NaF  + BrK

Double replacement:

It is the reaction in which two compound exchange their ions and form new compounds.

AB + CD → AD +CB

2)   2Cu + MnCl₂       →      2CuCl + Mn

Single replacement:

It is the reaction in which one elements replace the other element in compound.

AB + C → AC + B

3) CO₂     →    O₂  + C

Decomposition reaction:

It is the reaction in which one reactant is break down into two or more product.

AB → A + B

4) C + 2H₂      →    CH₄

Combination reaction:

It is the reaction in which two or more simple substance react to give one or more complex product.

Answer:

Sn, Sb, Te, Ga, As

Explanation:

a. 627.1 m/s

b.  the rate of effusion of ethane = 1.7 faster than hexane

Given

T = 200 + 273 = 473 K

Required

a. the gas speed

b. The rate of effusion comparison

Solution

a.

Average velocities of gases can be expressed as root-mean-square averages. (V rms)  

[tex]\large {\boxed {\bold {v_ {rms} = \sqrt {\dfrac {3RT} {Mm}}}}[/tex]

R = gas constant, T = temperature, Mm = molar mass of the gas particles  

From the question  

R = 8,314 J / mol K  

T = temperature  

Mm = molar mass, kg / mol  

Molar mass of Ethane = 30 g/mol = 0.03 kg/mol

[tex]\tt v=\sqrt{\dfrac{3\times 8.314\times 473}{30} }=627.1~m/s[/tex]

b. the effusion rates of two gases = the square root of the inverse of their molar masses:  

[tex]\rm \dfrac{r_1}{r_2}=\sqrt{\dfrac{M_2}{M_1} }[/tex]

M₁ = molar mass ethane =30

M₂ =  molar mass hexane = 86

[tex]\tt \dfrac{r_1}{r_2}=\sqrt{\dfrac{86}{30} }=1.7[/tex]

the rate of effusion of ethane = 1.7 faster than hexane

Answer: The time after which the concentration of [tex]SO_2Cl_2[/tex] fall to 12.5% of its initial value is 26.2 hours

Explanation:

Expression for rate law for first order kinetics is given by:

[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]

where,

k = rate constant  

t = age of sample

a = let initial amount of the reactant  = 100

a - x = amount left after decay process  = 12.5

a) for completion of half life:  

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]

[tex]k=\frac{0.693}{8.75hour}=0.0792hour^{-1}[/tex]

b) for concentration to fall to 12.5 % of initial value  

[tex]t=\frac{2.303}{0.0792}\log\frac{100}{12.5}[/tex]

[tex]t=26.2hours[/tex]

The time after which the concentration of [tex]SO_2Cl_2[/tex] fall to 12.5% of its initial value is 26.2 hours

Answer:

It's considered a limited resource because there is a limited amount of freshwater found on Earth's surface. Explain why the amount of water per person differs between countries. It differs because in the different countries it is distributed unevenly.

Explanation:

looked it up

Answer:

6.25%

Explanation:

Given data:

Half life of lutetium-117 = 6.75 days

Percentage remaining after 27 days = ?

Solution;

Number of half lives = Time elapsed / half life

Number of half lives = 27 days / 6.75 days

Number of half lives = 4

At time zero = 100%

At first half life = 100%/2 = 50%

At second half life = 50%/2 = 25%

At 3rd half life = 25%/2 = 12.5%

At 4th half life = 12.5%/2 = 6.25%

Answer:

Contemporary light microscopes are able to magnify objects up to about a thousand times. Since most cells are between 1 and 100 μm in diameter, they can be observed by light microscopy, as can some of the larger subcellular organelles, such as nuclei, chloroplasts, and mitochondria.

Answer:

Scientists must collect accurate information that allows them to make evolutionary connections among organisms. Similar to detective work, scientists must use evidence to uncover the facts. In the case of phylogeny, evolutionary investigations focus on two types of evidence: morphologic (form and function) and genetic.

Explanation:

This what I think

Answer:

C

Explanation:

Just like a Alligator or Croc, they evolved from the dinosuar's. The scientest KNOW THIs mainly because they have compared the fossil's of a crocidile THEN and a corcidile NOW (Just a example)

Hope this helps and pls mark brainlest!

Answer:

the particles expand and the kinetic energy i think moves slower

Explanation:

Answer:

Absolute zero is the temperature at which the particles of matter (molecules and atoms) are at their lowest energy points. Some people think that at absolute zero particles lose all energy and stop moving. This is not correct. ... Scientists use lasers to slow atoms when cooling objects to very low temperatures.

Answer:

I think scientists should not clone the wooly mammoth because our environment is already working great without them and bringing them back has a chance to hurt the environment or even destroy it also wooly mammoths were exists about 3700 years ago and the world had changed A LOT from then so we could end up hurting the mammoth by putting it in a world that has changed a lot from when the wooly mammoth was actually alive.

Answer:

C. 1.5 m copper(II) sulfate(aq)

Explanation:

I say this because a copper is a metal and a metal always has the highest melting and boiling point. A metal is also malleable, can dissolve in water, and a good conductor of electricity. All the other answers have all the nonmetals in them like Carbon, Oxygen, Chlorine, and etc. Nonmetals do not have a high boiling point. They basically are brittle. Therefore, the final answer is C.

Answer:

elllo

Explanation:

Answer:

Covalent bonds form when electrons are shared between atoms and are attracted by the nuclei of both atoms.

Answer:

C) The products have more energy stored in their chemical bonds.

Explanation:

In such reactions that absorb energy, the products have more energy stored in their chemical bonds.

For endothermic changes, heat is absorbed from the surrounding hence the surrounding becomes colder at the end of the changes.

The heat energy level of the products is higher than that of the reactants.