Help for chem/physics

Answer:

IF the match is stuck on the side it could chach burning hot.

2) the burn peices looks like its burned and it becomes black since of it.

Explanation:

Answer:

A.) because they have delocalized electrons

Explanation:

This is right on edg. 2020

Answer:

Bruzaaubrey is 100% correct

Explanation:

Make sure to mark bruzaaubrey brainliest :)

Answer:

[tex]E=1.98\times 10^{-31}\ J[/tex]

Explanation:

Given that,

The frequency of a wave, f = 300 Hz

We need to find the energy of a wave. The formula for the energy of a wave is given by :

E = hf,

Where h is Planck's constant

[tex]E=6.63\times 10^{-34}\times 300\\\\=1.98\times 10^{-31}\ J[/tex]

So, the energy of the wave is [tex]1.98\times 10^{-31}\ J[/tex].

High concentrations of carbon dioxide make it harder for marine animals to respire (to extract oxygen from seawater). This, in turn, makes it harder for these animals to find food, avoid predators, and reproduce. Low concentrations of oxygen can have similar effect

Becay the Ocean's Carbon Balance. The idea seemed simple enough: the more carbon dioxide that people pumped into the atmosphere by burning fossil fuels, the more the oceans would absorb. ... Water trapped at the surface would become saturated, at which point, the ocean would slow its carbon uptake.

Explanation:

What volume of silver metal will weigh exactly 2500.0 g. The density of silver is 10.5 g/cm3. cm3 = 2500.0 g / 10.5 g/cm3 = 238 cm3

What is the density of a piece of wood that has a mass of 25.0 grams and a volume of 29.4 cm3? d = .85 g/cm3

Answer:

[tex]\%m/m=14\%[/tex]

Explanation:

Hello!

In this case, since the molarity of magnesium chloride (molar mass = 95.211 g/mol) is 1.672 mol/L and we know the density of the solution, we can first compute the concentration in g/L as shown below:

[tex][MgCl_2]=1.672\frac{molMgCl_2}{L}*\frac{95.211gMgCl_2}{1molMgCl_2}=159.2\frac{gMgCl_2}{L}[/tex]

Next, since the density of the solution is 1.137 g/mL, we can compute the concentration in g/g as shown below:

[tex][MgCl_2]=159.2\frac{gMgCl_2}{L}*\frac{1L}{1000mL}*\frac{1mL}{1.137g}=0.14[/tex]

Which is also the by-mass fraction and in percent it turns out:

[tex]\%m/m=0.14*100\%\\\\\%m/m=14\%[/tex]

Best regards!

Answer:

q

Explanation:

Answer:

oxygen is the most abundant element on the earth.

Answer: B

Explanation:

Mg and Cl are in the same row aka period. Elements in the same period have similar properties like electron shells so the second option is the best answer

Answer:

A. C3H3O

Explanation:

We have the following data:

m = mass of organic compound = 1.038g

Then mass of CO2 is 2.48g

Also mass of H2O is 0.510g

To calculate percentage of carbon = 12 x mass of CO2 x 100/44 x mass of organic compound

This gives us 65.1 percent

Formula to calculate percentage of H=

2 x mass of water x 100/18 x mass of organic compound.

= 2 x 0.510 x 100/18x 10038

This gives 5.4%

Percentage of Oxygen =100-(percentageof carbon +percentageof H)

= 100-(65.1+5.4)

= 100-70.5

= 29.5

We have to calculate emperical formula:

For C = 65.1

65.1/12

= 5.4

= 5.4/1.8

=3

For H=5.4

5.4/1

= 5.4

= 5.4/1.8

=3

For O = 29.5

= 29.5/16

= 1.8

= 1.8/1.8

=1

So the emperical formula of organic compound is given as

C3H3O1

= C3H3O

(The atomic weights of C, H, O are 12,1,16)

Answer:

so i got 34.5

Explanation:

Answer:

The second answer

Explanation:

Phase changes is an example of physical change because it only changes the substance's appearance.

Answer: 1 and 4 are the answers

Explanation: because when you mix a sub since and it will have a chemical change

Answer:

The answer is letter A.

A. A magnetic field occurs near a wire that has no current.

Because magnetic field occur near a current carrying wire.

Answer:

it is calcium. it is in group(llA).

Answer:

hope it is helpful to you

Answer:

3.228x10⁻⁴ moles of Na2S2O3 are required

Explanation:

In iodometry, the reaction of KIO3 with Na2S2O3 is:

KIO3 + 6 Na2S2O3 + 6H⁺ → KI + 3Na2S4O6 + 3H2O + 6Na⁺

Where 6 moles of Na2S2O3 reacts per moles of KIO3.

The moles of Na2S2O3 required to reach endpoint when 0.0000538 moles of KIO3 are:

0.0000538 moles of KIO3 * (6 moles Na2S2O3 / 1 mol KIO3) =

The way one determines a percent composition from an empirical formula is to divide the total mass of each element by the mass of the compound and multiply by 100%.

Empirical formula is a notation that indicates the ratios of the various elements present in a compound, without regard to the actual numbers.

The empirical formula of a compound is the simplest ratio that can exist between the constituent elements of a compound.

However, the percent composition of a compound can be determined by dividing the total mass of each element by the mass of the compound and multiply by 100%.

Learn more about empirical formula at: https://brainly.com/question/14044066

#SPJ2

Answer:

AsH(2.) CHEBI:33104

Explanation:

Molecular Weight is : 75.9296 g/mol

Answer:

Explanation:

Hello!

In this case, since the undergoing chemical reaction is:

[tex]2NO+O_2\rightleftharpoons 2NO_2[/tex]

The equilibrium expression in terms of pressures is:

[tex]Kp=\frac{p_{NO_2}^2}{p_{NO}^2p_{O_2}}[/tex]

Thus, for the initial conditions, we compute the initial pressures of both nitric oxide and oxygen:

[tex]p_{NO}^{0}=\frac{12.0g*0.082\frac{atm*L}{mol*K}*298.15K}{30g/mol*10.0L}=0.978atm\\\\ p_{O_2}^{0}=\frac{12.0g*0.082\frac{atm*L}{mol*K}*298.15K}{32g/mol*10.0L}=0.917atm[/tex]

Next, since the equilibrium pressure is 1148 mmHg or 1.51 atm, we can write:

[tex]p_T=p_{NO_2}+p_{NO}+p_{O_2}\\\\1.51=2x+0.978-2x+0.917-x\\\\1.51=1.90-x\\\\x=0.39atm[/tex]

Thus, the Kp turns out:

[tex]Kp=\frac{(2*0.39)^2}{(0.978-2*0.39)^2(0.917-x)} \\\\Kp=29.4[/tex]

Best regards!

Answer:

The answer is Option a, that is "−9kJmole,5kJmole".

Explanation:

Please find the complete question in the attached file.

In the question, it uses the catalyst inside a process, which does not modify the process eigenvalues, however, it decreases the active energy with an enthalpy of -9kJmole, and also the power for activating decreases around 13 to 5 kJ mole, that's why the choice a is correct.

Answer:energy

Explanation:needed points sorry

Answer:

A.

Explanation:

elctrolytes decomposes

Answer:

D. ionizes

Explanation:

Answer:

Many areas of the United States experience explosive population growth. The more people that reside someplace, the more demand there is for water there. Often these urban-growth expansions are unplanned and place extraordinary stress on the water supply system, mainly on the groundwater. The stress often depletes groundwater supply, thereby causing wells to dry up. Then water must be brought from somewhere else to support the local population.

Such situations have occurred all over the United States. For example, increased population growth in the southwestern United States has significantly lowered the water table 50 to 200 feet (depending on the area) since the 1940s. Managing urban growth, efforts to reduce water demand, conservation of the resource, and attempts to increase the water supply all address the problem of exceeding water resource limits.

Human activities affect groundwater quality.

Here are some sources and possible solutions to groundwater pollution:

Agriculture—Reduce usage of pesticides and fertilizers.

Landfills—Monitor for leakage and repair linings.

Underground storage tanks—Remove damaged and unused tanks.

Household wastes—Properly dispose of household hazardous waste.

Septic tank leaks—Properly maintain and repair tanks.

Explanation:

This came from the K12 learning course read this and the answer will be there. I underlined the important parts for the answer.

Explanation:

i cant even see any thing

Answer: A and D

Explanation:

The energy produced in the burning of gasoline = 45 kJ/g. So, amount of energy produced by burning 48 L gasoline = 45 kJ/g×36960 g = 1663200 kJ.

Explanation:

The IUPAC system of nomenclature aims to ensure

that every organic compound has a unique, unambiguous name.that the IUPAC name of any compound conveys the structure of that compound to a person familiar with the system.

One way of checking whether the name you have given to an alkane is reasonable is to count the number of carbon atoms implied by the chosen name. For example, if you named a compound 3‑ethyl-4‑methylheptane, you have indicated that the compound contains a total of 10 carbon atoms—seven carbon atoms in the main chain, two carbon atoms in an ethyl group, and one carbon atom in a methyl group. If you were to check the given structure and find 11 carbon atoms, you would know that you had made a mistake. Perhaps the name you should have written was 3‑ethyl-4,4‑dimethylheptane!