can someone help me?​

Answer:

44.45 g of tetrahydrofuran.

Explanation:

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

Volume of tetrahydrofuran = 50 mL

Density of tetrahydrofuran = 0.889 g/mL

Mass of tetrahydrofuran =?

Density of a substance is simply defined as the mass of the substance per unit volume of the substance. Mathematically, density is expressed as shown below:

Density = mass / volume

With the above formula, we shall determine the mass of tetrahydrofuran needed. This can be obtained as follow:

Volume of tetrahydrofuran = 50 mL

Density of tetrahydrofuran = 0.889 g/mL

Mass of tetrahydrofuran =?

Density = mass / volume

0.889 = mass / 50

Cross multiply

Mass = 0.889 × 50

Mass of tetrahydrofuran = 44.45 g

Therefore, the student should weigh out 44.45 g of tetrahydrofuran.

The mass allowance of Vitamin C for children aged 4-8 years is equal to 0.025 grams.

A mole can be defined as a standard unit that can be utilized to evaluate the number of entities such as atoms, molecules, ions, or other particular particles in a particular amount of the substance.

The number of elementary entities present in one mole of any chemical substance was found to be equal to 6.023 × 10²³ which is also known as the Avogadro number.

Given, the number of moles of vitamin C = 0.000142 moles

Given, the molecular formula of Vitamin C is C₆H₈O₆.

The mass of one mole of C₆H₈O₆ = 176 g

One mole of Vitamin C has mass = 176 g

0.000142 mol of Vitamin C has mass  = 0.000142×176 = 0.025 g

Therefore, the mass of 0.000142 mol of Vitamin C is 0.025 g.

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Answer:

STP values are most often cited for gases because their characteristics change dramatically with temperature and pressure. One common definition of STP is a temperature of 273 K (0° Celsius or 32° Fahrenheit) and the standard pressure of 1 atm. Under these conditions, one mole of a gas occupies 22.4 L.

Answer:

I'm pretty sure its the one that says very little at the beginning but if I get it wrong I'm sorry

Answer: 1and 4

Explanation: iron is an element not an alloy. An ionic lattice is not bonded covalently.

Answer:

The conditions are

1) Small enough

2) Electronegative atom

3) highly electronegative

4) lone pair of electrons

The correct statement therefore is

It needs to be small enough not to bump into other atoms when approaching the 1s orbital of the hydrogen, it needs to carry at least one electronegative atom, it needs to be highly electronegative enough to create a delta on the connected hydrogen, and it needs to have at least one lone pair of electrons.

Explanation:

Hydrogen bonding is a type of intermolecular bond that occurs between the partial positive charge (delta) on a hydrogen atom bonded to a small highly electronegative element (like nitrogen, oxygen or fluorine) and the free electrons on another electronegative element of another molecule.

The hydrogen atom with the partial positive charge (delta) is known as the hydrogen bond donor, while the electronegative element, carrying lone electrons is called the hydrogen bond acceptor.

Let's take a deeper look at these terms:

1) Hydrogen bond donor

Using water (H₂O) as an example, the high electronegativity of the oxygen atom covalently bonded to the hydrogen atom draws the lone electron in the 1s orbital of the hydrogen atom, creating a partial positive charge (d⁺) on the hydrogen atom. This is what happens within one water molecule

2) Hydrogen bond acceptor

When two or more molecules of water interact, the partial positive charge (d⁺) on the hydrogen atom of one molecule, is attracted to the valence or free electrons on the oxygen atom of a nearby molecule of water thus creating a dipole-dipole intermolecular bond known as a hydrogen bond.

For the hydrogen bond to be effective, the electronegative atom bonded to the hydrogen acting as the hydrogen bond donor in the first water molecule needs to be small enough so as not to disrupt the 1s orbital of the hydrogen atom. The smaller the size of the electronegative atom, the stronger the partial negative charge created on the hydrogen atom.

The valence or free pair of electrons on the electronegative (oxygen) atom of the second molecule of water (hydrogen bond acceptor) is what attracts the partial positive charge on the hydrogen atom to create the hydrogen bond

Answer:

84.8 mL

Explanation:

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

Mass of CuNO₃ = 3.53 g

Molarity of CuNO₃ = 0.330 M

Volume of solution =?

Next, we shall determine the number of mole in 3.53 g of CuNO₃. This can be obtained as follow:

Mass of CuNO₃ = 3.53 g

Molar mass of CuNO₃ = 63.5 + 14 + (16×3)

= 63.5 + 14 + 48

= 125.5 g/mol

Mole of CuNO₃ =?

Mole = mass / Molar mass

Mole of CuNO₃ = 3.53 / 125.5

Mole of CuNO₃ = 0.028 moles

Next, we shall determine the volume of the solution. This can be obtained as follow:

Molarity of CuNO₃ = 0.330 M

Mole of CuNO₃ = 0.028 moles

Volume of solution =?

Molarity = mole /Volume

0.330 = 0.028 / Volume

Cross multiply

0.330 × Volume = 0.028

Divide both side by 0.330

Volume = 0.028 / 0.330

Volume = 0.0848 L

Finally, we shall convert 0.0848 L to millilitres (mL). This can be obtained as follow:

1 L = 1000 mL

Therefore,

0.0848 L = 0.0848 L × 1000 mL / 1 L

0.0848 L = 84.8 mL

Therefore, the volume of the solution is 84.8 mL.

Hello there!

Aspartame has 4 kilocalories of energy per gram and table sugar has 3.9 kilocalories. They are pretty much same but aspartame is 200 times sweeter than sucrose so probably would be aspartame that has more calories.

Answer:

Electrons in a hydrogen atom must be in one of the allowed energy levels. If an electron is in the first energy level, it must have exactly -13.6 eV of energy.

...

Energy Levels of Electrons.

Energy Level Energy

1 -13.6 eV

2 -3.4 eV

3 -1.51 eV

4 -.85 eV

Answer:

There are no options provided dude,

But i guess the  answer will be a metal with valency 2 for sure as the subscript given for N in 'M3N2' is 2 so the valency of the metal u need to select will be 2 for sure

It can be magnesium or some other if the provided options in real question has Mg then its the answer

Answer:

D 27.74%

Explanation:

Percent composition of Magnesium (Mg) in Magnesium Phosphate compound ie Mg3(PO4)2 = 27.74%

Answer:

The answer is D

Explanation:

I took the test

Answer:

The correct answer is A :))

Answer:

b. temperature difference

Answer:

[H2]2[S2][H2S]2Kc=[H2]2[S2][H2S]2

Explanation:

2H2S(g)⇋2H2(g)+S2(g)2H2S(g)⇋2H2(g)+S2(g)

The equilibrium constant expression in terms of concentrations is:

Kc=[H2]2[S2][H2S]2Kc=[H2]2[S2][H2S]2.

The equilibrium expression for the given reaction can be written in terms of equilibrium constant which is the ratio of power of molar concentration of the product to the product of power of molar concentration of the reactants.

Equilibrium is a state for a reversible reaction where, the rate of forward reaction is equal to the rate of backward reaction. The rate of a reaction is the rate of decrease in the concentration of reactants or the rate of increase in the concentration of the products.

The given reaction at equilibrium state is written as:

[tex]\rm 2H_{2}S (g)\leftrightharpoons 2H_{2} (g)+ S_{2}(g)[/tex]

The equilibrium constant Kb is ratio of power of molar concentration of the product to the product of power of molar concentration of the reactants.

[tex]Kb = \rm \frac{[H_{2}S]^{2}}{[H_{2}]^{2} [S_{2}]}[/tex]

The rate of the reaction will be r = Kb [H₂]² [S₂].

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Answer:

Solids for sure

particles of solid cant flow.

Answer:

B)Solids

Solids have  tightly packed particles unlike liquids and gases whose particles can move freely but rate of movement is highest in gas while compared to water

Answer:

0.591 g of magnesium phosphate is the theoretical yield.

Magnesium nitrate is the limiting reactant.

Explanation:

Hello!

In this case, since the balanced reaction turns out:

[tex]3Mg(NO_3)_2+2Na_3PO_4\rightarrow Mg_3(PO_4)_2+6NaNO_3[/tex]

Next, we compute the grams of magnesium phosphate yielded by each reactant, considering the present mole ratios and molar masses:

[tex]m_{Mg_3(PO_4)_2}^{by\ Mg(NO_3)_2}=1.00gMg(NO_3)_2*\frac{1molMg(NO_3)_2}{148.31gMg(NO_3)_2}*\frac{1molMg_3(PO_4)_2}{3molMg(NO_3)_2} *\frac{262.86gMg_3(PO_4)_2}{1molMg_3(PO_4)_2} \\\\m_{Mg_3(PO_4)_2}^{by\ Mg(NO_3)_2}= 0.591gMg_3(PO_4)_2\\\\m_{Mg_3(PO_4)_2}^{by\ Na_3PO_4}=1.00gNa_3PO_4*\frac{1molNa_3PO_4}{163.94gNa_3PO_4}*\frac{1molMg_3(PO_4)_2}{2molNa_3PO_4} *\frac{262.86gMg_3(PO_4)_2}{1molMg_3(PO_4)_2} \\\\m_{Mg_3(PO_4)_2}^{by\ Na_3PO_4} = 0.802gMg_3(PO_4)_2[/tex]

Thus, we infer that the correct theoretical yielded mass is 0.591 g as magnesium nitrate is the limiting reactant for which it produces the fewest grams of product.

However, is not possible to compute the percent yield since no actual yield is given, and must be provided or indicated by the problem or an experiment and it not here, nevertheless, you may compute the percent yield by dividing the actual yield by the theoretical and then multiplying by 100:

[tex]Y=\frac{actual}{0.591g}*100\%[/tex]

Best regards!

Answer:

Explanation:

the average rate of change of the concentration =

( initial concentration - final concentration ) / time

Initial concentration = 2.000 M

the average rate of change of the concentration = .0540 M/s

time = 2 s

Putting the values

.0540 =  (2.000 - X ) / 2

0.108 = 2.000 - X

X = 1.892 M .

Final concentration = 1.892 M .

Answer:

Kp = Kc (RT) ^(-2)

Explanation:

For the reaction;

N2 (g) + 3H2 ⇄ 2NH3(g)

We can write;

Kc = [NH3]^2/[N2] [H2]^3

But

Kp = pNH3^2/pN2 . PH2^3

To convert from Kc to Kp

Kp = Kc (RT) ^Δn

where Δn is the change in number of moles going from reactants

to products.

For this reaction;

Δn = 2- (3+1) = -2

Kp = Kc (RT) ^(-2)

Answer:

Explanation:

Energy of falling radiation having wavelength of 265 nm

= h c / λ where h is plank's constant , c is velocity of light and λ is wavelength of radiation . Putting the values

Energy of light photon = 6.6 x 10⁻³⁴ x 3 x 10⁸ / 265 x 10⁻⁹

= .0747 x 10⁻¹⁷

= 7.47 x 10⁻¹⁹ J .

Work function of sodium is 4.41 x 10⁻¹⁹

So kinetic energy of ejected electron = energy of falling photon - work function

= 7.47 x 10⁻¹⁹ - 4.41 x 10⁻¹⁹

= 3.06 x 10⁻¹⁹ eV .

Answer: The new pressure if the volume is compressed to 2.0 liters at a temperature of 450K is 2.7 atm

Explanation:

The combined gas equation is,

[tex]\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}[/tex]

where,

[tex]P_1[/tex] = initial pressure of gas = 1.00 atm

[tex]P_2[/tex] = final pressure of gas = ?

[tex]V_1[/tex] = initial volume of gas = 3.60 L

[tex]V_2[/tex] = final volume of gas = 2.0 L

[tex]T_1[/tex] = initial temperature of gas = [tex]300K[/tex]

[tex]T_2[/tex] = final temperature of gas = [tex]450K[/tex]

Now put all the given values in the above equation, we get:

[tex]\frac{1.00\times 3.60}{300}=\frac{P_2\times 2.0}{450}[/tex]

[tex]P_2=2.7atm[/tex]

The new pressure is 2.7 atm

Answer: [tex]LiF[/tex] , [tex]AlCl_3[/tex] and [tex]BeCl_2[/tex]

Explanation:

An ionic bond is formed when an element completely transfers its valence electron to another element. The element which donates the electron is known as electropositive element or the metal and the element which accepts the electrons is known as electronegative element or non metal.

A covalent bond is formed when an element shares its valence electron with another element. This bond is formed between two non metals.

[tex]LiF[/tex] , [tex]AlCl_3[/tex] and [tex]BeCl_2[/tex] contain ionic bonds as they aremade up of metals and non metals.

Answer:

C8H16O4

Explanation:

C2H4O= 24+4+16

44

n=molar mass/empirical formula

n=176.21/44

=4

Therefore

Molar Formula= (C2H4O)4=C8H16O4

Answer: Thermal Equilibrium

Explanation:

Answer:

temperature  

Explanation:

I think that's it i'm sorry if i'm wrong

Answer:

it develops from the womb

Answer:

outer cells of the blastocyst

Explanation:

on edg:)

Answer:

a period

Explanation:

Answer: The row of elements across the periodic table is called "periods".

Explanation:

In the Periodic Table, there are seven rows of elements, which is called periods.

Answer: the line-emission spectrum of an atom is caused by the energies released when electrons. releases energy of only certain values.

Answer:

4.82 moles of Ag.

Explanation:

We'll begin by calculating the number of mole in 450.98 g of Cu(NO₃)₂. This can be obtained as follow:

Molar mass of Cu(NO₃)₂ = 63.5 + 2[14 + (16×3)]

= 63.5 + 2[14 + 48]

= 63.5 + 2[62]

= 63.5 + 124

= 187.5 g/mol

Mass of Cu(NO₃)₂ = 450.98 g

Mole of Cu(NO₃)₂ =?

Mole = mass /Molar mass

Mole of Cu(NO₃)₂ = 450.98 / 187.5

Mole of Cu(NO₃)₂ = 2.41 moles

Next, we shall determine the number of mole of Cu needed to produce 450.98 g (i.e 2.41 moles) of Cu(NO₃)₂. This can be obtained as follow:

Cu + 2AgNO₃ —> Cu(NO₃)₂ + 2Ag

From the balanced equation above,

1 mole of Cu reacted to produce 1 mole of Cu(NO₃)₂.

Therefore, 2.41 moles of Cu will also react to produce 2.41 moles of Cu(NO₃)₂.

Thus, 2.41 moles of Cu is needed for the reaction.

Finally, we shall determine the number of mole of Ag produced from the reaction. This can be obtained as follow:

From the balanced equation above,

1 mole of Cu reacted to produce 2 moles of Ag.

Therefore, 2.41 moles of Cu will react to produce = 2× 2.41 = 4.82 moles of Ag.

Thus, 4.82 moles of Ag were obtained from the reaction.

Answer:

0.73g/cm^3

Explanation:

d=m/v

d=11/15

d=0.73