i am having trouble solving it pls help

Answer:

A.) pure substance

Explanation:

edge 2021

Answer:

Lithium oxide, Li₂O.  

Explanation:

Hello!  

In this case, according to the given amounts, it is possible to write down the chemical reaction as shown below:

[tex]M_2O+H_2\rightarrow 2M+H_2O[/tex]  

Which means that the metallic oxide has the following formula: M₂O. Next, we can set up the following proportional factors according to the chemical reaction:

Thus, we perform the operations in order to obtain:

[tex]\frac{10X}{(2X+16)}=2.32[/tex]  

So we solve for x as shown below:

[tex]10X=2.32(2X+16)\\\\10X=4.64X+37.12\\\\X=\frac{37.12}{10-4.64}\\\\X= 6.93g/mol[/tex]  

Whose molar mass corresponds to lithium, and therefore, the metallic oxide is lithium oxide, Li₂O.  

Best regards!

So, Ecosystem Diversity is a term that describes how different habitats of organisms are. For example, the fact that our planet has deserts, tundras but also estuaries is a sign of the diversity of its ecosystems. Species diversity refers to the number of different species that inhabit a specific ecosystem or the whole biosphere; the more, the better for species diversity. Genetic diversity is the term we are looking for; it means the variation in genes (usually in one species) that leads to different inheritable traits (in members of the same species). For example eye color is an inheritable trait that showcases genetic diversity since there are many genes that determine a different color such as brown, blue, green etc. (even though the environment plays a role too). Finally, natural selection is a theory about the survival of the fittest due to competition. It relates to inheritable traits and their diversity but it does not describe them.

Answer:

Option B, When the cell needs to move a compound against its concentration gradient.

Explanation:

A cell uses active transport when it has to transport substances against the concentration gradient across its membrane.

In active transport additional energy is used (generally provided by energy molecules like ATP) to push the substance across any membrane from low concentration side  to high concentration side.

Option B is correct

Answer:

Exotérmica.

Explanation:

¡Hola!

En este caso, dado que la mayoría de reacciones de combustión son exotérmicas, al generar calor en los productos, es posible inferir que esta reacción, referida a la combustion de metano es exotérmica debido a lo anteriormente mencionado, ya que el término de energía de reacción, 531 kcal, está al lado de los productos, lo que quiere decir que es energía generada.

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Answer:

5

Explanation:

Given that the formula is;

1/λ= R(1/nf^2 - 1/ni^2)

λ = 93.7 nm or 93.7 * 10^-9 m

R= 1.097 * 10^7 m-1

nf = ?

ni = 1

From;

ΔE = hc/λ

ΔE = 6.63 * 10^-34 * 3* 10^8/93.7 * 10^-9

ΔE = 21 * 10^-19 J

ΔE = -2.18 * 10^-18 J (1/nf^2 - 1/ni^2)

21 * 10^-19 J = -2.18 * 10^-18 J (1/nf^2 - 1/ni^2)

21 * 10^-19/-2.18 * 10^-18 = (1/nf^2 - 1/1^2)

-0.963 = (1/nf^2 - 1)

-0.963 + 1 = 1/nf^2

0.037 = 1/nf^2

nf^2 = (0.037)^-1

nf^2 = 27

nf = 5

Explanation:

Cause the clumps are so compacted together that it is harder to brake apart but the one that are separated are easy cause they do not have all the pressure on them and when they go to add reaction it is faster

Answer:

CN

CH

C9H20

P205

BH3

Explanation:

Answer:

a. True

Explanation:

The bond angle for methane is the angle determined by two consecutive hydrogen atoms and the central carbon atom.

Methane, a tetrahedron has the structural formula:

                             H

                              |

                    H  -   C   -  H

                              |

                             H            Methane, CH4

The bond angle is the angle between the H-C-H atoms and is 109.5degrees.

Answer:

Theoretically you could be totally unrelated to your sister or share the exact same DNA as your brother. But because we are talking about so much DNA and so many different possible combinations, the percentage usually comes out to about 50%. Think about it like flipping a coin.

Explanation:

Explanation:

Theoretically you could be totally unrelated to your sister or share the exact same DNA as your brother. But because we are talking about so much DNA and so many different possible combinations, the percentage usually comes out to about 50%. 

Answer:

True

Explanation:

The arrangement of three groups COOH, CO, OH in the order of reducing boiling point is as follow -

 COOH > OH > CO

COOH gets strongly polarised due to the presence of electron withdrawing carboxy group and hence have strong H+ bonds as compared to that of alcohol.

Hence the given statement is true.

3.59 mol

1.836 x 10 ²⁵ molecules

Given

230 g SO2

30.5 moles LiNO3

Required

moles and molecules

Solution

mol = mass : molar mass

1 mol = 6.02 x 10²³ particles(molecules, atoms, ions)

1. 230 g x 1 mol/64,066 g  =3.59 mol

2. 30.5 moles x 6.02 x 10 ²³ molecules / 1 mol = 1.836 x 10 ²⁵ molecules

Answer:

110g/mol is the molar mass of compound A

Explanation:

The osmotic pressure of a solution could be obtained using the equation:

π = i*M*R*T -Solving molarity we can find the molar mass of the solute A-

Where π is osmotic pressure (7.38atm)

i is Van't Hoff's factor (1 for nonelectrolytes)

M is molarity (Our incognite)

R is gas constant (0.082atmL/molK)

T is absolute temperature (25°C + 273.15 = 298.15K)

Computing the values:

7.378atm = 1*M*0.082atmL/molK*298.15K

0.3018 mol/L is the concentration of the solution.

The volume of the solution is 15mL = 0.015L. Moles of the solute are:

0.3018 mol/L * 0.015L = 4.527x10⁻³ moles

Molar mass is the ratio between mass of the compound (0.50g) and the moles (4.527x10⁻³ moles). That is:

0.50g / 4.527x10⁻³ moles =

Answer:

A

Explanation:

Answer:

increase the chemical rate

[H⁺]=6.696 x 10⁻⁵

pH = 4.174

Given

The concentration of 0.000295 M (2.95 x 10⁻⁴ M) butanoic acid solution

Required

the [H+]  and pH

Solution

Butanoic acid is the carboxylic acid group. Carboxylic acids are weak acids

For weak acid :

[tex]\tt [H^+]=\sqrt{Ka.M}[/tex]

Input the value :

[H⁺]=√1.52 x 10⁻⁵ x 2.95 x 10⁻⁴

[H⁺]=6.696 x 10⁻⁵

pH = - log [H⁺]

pH = - log 6.696 x 10⁻⁵

pH = 5 - log 6.696

pH = 4.174

100g/220g*100 is the correct answer- I took the test

Answer:

answer:

given;

total gram=70+50+100=220g

total gram of chocolate=100g

percentage composition of chocolate=total gram of chocolate/total gram ×100%

=100g/220g ×100 is your answer

Decomposition: A substance breaks down to smaller species.

Answer:

d. Mass is the measure of the earth’s gravitational attraction of a body

This is FALSE. Mass is the measure of matter than an object contains.

Explanation:

b. An atom is the smallest particle of an element that still contains properties of the original element.

This is True

c. Gases can be colorless or colored

This is True

d. Mass is the measure of the earth’s gravitational attraction of a body

This is FALSE. Mass is the measure of matter than an object contains.

e. A pure substance has a fixed composition.

This is True.

Answer:

Probably Alkaline

Explanation:

Not sure at all.

Answer:

[tex][PCl_3]=[Cl_2]=0.068M[/tex]

[tex][PCl_5]=0.385M[/tex]

Explanation:

Hello!

In this case, since the equilibrium expression for the considered equation is:

[tex]Kc=\frac{[PCl_5]}{[Cl_2][PCl_3]}[/tex]

Which can be written in terms of the reaction extent and the ICE chart and the initial concentrations of 0.453 M as shown below:

[tex]83.3=\frac{x}{(0.453M-x)(0.453M-x)}[/tex]

We can solve for x as follows:

[tex]x=0.385M[/tex]

In such a way, we obtain the following concentrations at equilibrium:

[tex][PCl_3]=[Cl_2]=0.453M-0.385M=0.068M[/tex]

[tex][PCl_5]=0.385M[/tex]

Best regards!

Answer:

Explanation:

Molar heat capacity at constant volume Cv  of a gas = n x .5 R where n is degree of freedom of the gas molecules

CO₂ is a linear molecule , so number of degree of freedom =  3 + 2 = 5

3 is translational and 2 is rotational degree of freedom . There is no vibrational degree of freedom given .

So Cv = 5 / 2 R

= 2.5 R .

Answer:

Glass that will sink: alkali zinc borosilicate with a density of2.57 g/mL in a solution with a density of 2.46 g/mL; potash soda lead with a density of 3.05 g/mL in a solution with a density of 1.65 g/mL

Glass that will float: soda borosilicate with a density of 2.27 g/mL in a solution with a density of 2.62 g/mL; alkali strontium with a density of 2.26 g/mL in a solution with a density of 2.34 g/mL

Glass that will not sink or float: potash borosilicate with a density of2.16 g/mL in a solution with a density of 2.16 g/mL

Explanation:

The density of an object is a ratio of the mass (or quantity of matter in the object) to its volume.

Mathematically, density = mass/ volume.

The more dense an object, the higher will be its dense. Density can be thought of as a comparison of how heavy objects having the same are. Objects with a higher density, are heavier than objects with a lower density. For example, between equal volumes of air and water, water is heavier.

The density of solid object will determine whether it will float, sink or neither float nor sink in a given liquid. The conditions for floating of objects in a liquid is given as follows:

Density of solid > Density of liquid : solid will sink

Density of solid = Density of liquid : solid will neither sink nor float

Density of solid < Density of liquid : solid will float

Using the above criteria to analyze the given glass materials in their respective liquids:

Glass that will sink: alkali zinc borosilicate with a density of2.57 g/mL in a solution with a density of 2.46 g/mL; potash soda lead with a density of 3.05 g/mL in a solution with a density of 1.65 g/mL

Glass that will float: soda borosilicate with a density of 2.27 g/mL in a solution with a density of 2.62 g/mL; alkali strontium with a density of 2.26 g/mL in a solution with a density of 2.34 g/mL

Glass that will not sink or float: potash borosilicate with a density of2.16 g/mL in a solution with a density of 2.16 g/mL

Answer:

21.3g of Fe(NO₃)₃ are required to produce the same depression in freezing point of solution.

Explanation:

Freezing point depression is a colligative property which indicates, in determined mixture, the freezing point of solution is lower that the freezing point of the solvent, according the amount of solute.

Formula is: ΔT = Kf . m . i

Kf is the cryoscopic constant, which is particular for each solvent. We do not have that data, so we need to find it out in order to solve the question:

ΔT = Freezing point of pure solvent - Freezing point of solution.

This data is known → 6.40°C

m, means molality, moles of solute in 1kg of solvent. Let's get the moles of benzamide: 42.5 g . 1mol / 121g = 0.351 moles

m = 0.351 mol / 0.5kg = 0.702 m

As benzamide is an organic compound i, = 1. i are the number of ions dissolved in solution. Let's find out Kf:

6.40°C = Kf . 0.702 m . 1

6.40°C /0.702m = 9.11 °C/m.

Let's go to the next question.

ΔT is the same → 6.40°C

But this is, an inorganic salt, a ionic salt: Fe(NO₃)₃ →  1Fe³⁺  + 3NO₃⁻

For this case, we have 1 mol of Iron(III) and 3 nitrates, so i = 4

Let's replace data: 6.40°C = 9.11 °C/m . m . 4

6.40°C / (9.11 m/°C . 4) = 0.176 m

This data represents that, in 1 kg of solvent we have 0.176 moles of nitrate.

Mass of solvent X required in this case is 0.500 kg, so, the moles that are contained are: 0.500 kg . 0.176 mol/kg = 0.088 mol

Let's determine the mass of salt: 0.088 mol . 241.85g /1mol = 21.3 g

Answer:

electromagnetic field

Answer:

C Splitting atoms apart

Answer:

Explanation:

An internal force acts between elements of the system. Only external forces affect the motion of a system, according to Newton's first law. Newton's second law states that a net force on an object is responsible for its ... Prior to manned space flights, rocket sleds were used to test aircraft, missile equipment, and physiological