Lying in bed you notice that you get cold every time your brother opens the door. This is most closely associated with which step in the scientific method?

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:

mass of 1 molecule of CO2=44 g

mass of 2.71*10^22 of CO2=2.71*10^22*44=1.2*10^24g

now to convert grams into kilogram we know that

1000 g=1kg

1.2*10^24=1.2*10^24/1000=1.2*10^21

According to Avogadro's number concept,there are 1.979×10[tex]^-3[/tex] kilograms in 2.71 ×10²² molecules of CO₂.

Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.

It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .

According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.

Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number. Mass is calculated as, number of molecules/Avogadro's number×molar mass

Substitution in above formula gives, mass=2.71×10²²/6.023×10²³×44=1.979 g or 1.979×10[tex]^-3[/tex] kg.

Thus, there are  1.979×10[tex]^-3[/tex] kg in 2.71×10²² molecules of carbon dioxide.

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Answer:

C6H6 has the strongest intermolecular force

i think

Answer:

H2O

Explanation:

Because it is a hydrogen bond which is said to be the strongest bond between the H and a N,O, or F combination

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:

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:

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) =

Answer:energy

Explanation:needed points sorry

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:

[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:

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)

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.

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.

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:

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!

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!

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%.

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Answer:

A.

Explanation:

elctrolytes decomposes

Answer:

D. ionizes

Explanation:

Heat capacity of Calorimeter = 10.7 J/°c

Heat lost=Heat gained

Q in = Q out

-Q lost(hot water)=Q gained (cold water+calorimeter)

-m.c.Δt=m.c.Δt+C.Δt

[tex]\tt \rightarrow -50\times 4.18\times (32.7-43)=50\times 4.18\times (32.7-22.9)+(32.7-22.9)\times C_{cal}\\\\\rightarrow 2152.7=2048.2+9.8\times C_{cal}\\\\104.5~J=9.8\times C_{cal}\\\\C_{cal}=\dfrac{104.5}{9.8}=10.7~J/^oC[/tex]

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:

AsH(2.) CHEBI:33104

Explanation:

Molecular Weight is : 75.9296 g/mol

Answer:

q

Explanation:

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:

Titration is a technique to determine the concentration of an unknown solution. As illustrated in the titration setup above, a solution of known concentration (titrant) is used to determine the concentration of an unknown solution (titrand or analyte).

Typically, the titrant (the solution of known concentration) is added through a burette to a known volume of the analyte (the solution of unknown concentration) until the reaction is complete. Knowing the volume of titrant added allows us to determine the concentration of the unknown analyte. Often, an indicator is used to signal the end of the reaction, the endpoint. Titrant and analyte is a pair of acid and base. Acid-base titrations are monitored by the change of pH as titration progresses.

Let us be clear about some terminologies before we get into the discussion of titration curves.

Answer:

From the numerical steps highlighted under explanation, the average atomic mass of bromine is 79.91 u

Explanation:

The steps to be taken will involve;

1) Find the number of isotopes of bromine.

2) Identify the atomic mass and relative abundance of each of the isotopes.

3) Multiply the atomic mass of each of the isotopes by their corresponding values relative abundance value.

4) Add the value in step 3 above to get the average atomic mass of bromine.

Now;

Bromine has 2 isotopes namely;

Isotope 1: Atomic mass = 78.92amu and a relative abundance of 50.69%.

Isotope 2: Atomic mass = 80.92amu and a relative abundance of 49.31%.

Using step 3 above, we have;

(78.92 × 50.69%)

And (80.92 × 49.31%)

Using step 4 above, we have;

(78.92 × 50.69%) + (80.92 × 49.31%) ≈ 79.91 u

The atomic mass of bromine has been calculated as 79.9062 amu.

The relative atomic mass of the element has been given as the mass of each isotope with respect to their abundance.

The atomic mass has been given as:

[tex]amu=\sum mass\;\times\;\% Abundance[/tex]

The available isotopes of Bromine have been:

Isotope 1 = 78.92 amu, and 0.5069 % abundance

Isotope 2= 80.92 amu, and 0.4931 % abundance

Submitting the values for the atomic mass unit of bromine ([tex]amu_{\text{Br}}[/tex]):

[tex]amu_{\text {Br}}= (78.92\;\times\;0.5069)\;+\;(80.92\;\times\;0.4931)\\amu_{\text{Br}}=40.0045\;+\;39.9016\\amu_{\text{Br}}=79.9062[/tex]

The atomic mass of bromine has been calculated as 79.9062 amu.

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