Can someone help me please

Answer:

As the world changes, plants and animals change with it. Aside from a few living fossils, the species we see today are very different from species that lived in the past. Thus, the fossil record can be used to show that organisms changed to meet new conditions. This is the result of evolution of species over time.

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Explanation:

The molar mass of the unknown nonelectrolyte compound is

Using the formula;

∆T = K m i

Where;

K = freezing point depression constant

m = molality of the solution

i = Van't Hoft factor

Note that i = 1 since the compound is a nonelectrolyte.

To find molality;

Number of moles = 0.520 g/Molar mass

Let the molar mass of the unknown compound be MM

Number of moles = 0.520 g/MM

Number of kilograms of solvent = 4.12 g/1000 = 0.00412 Kg

Molality = 0.520 g/MM * 1/0.00412 Kg

Freezing point depression is 4.20 °C

To find the molar mass of the compound;

4.20 °C = 3.90 °C/m *  0.520 g/MM * 1/0.00412 Kg

4.20  = 492.23/MM

MM = 492.23/4.20

MM = 117.19 g/mol

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Answer:

this is a required answer. look it once.

Answer:

See explanation

Explanation:

The elements in group form univalent positive ions and element in group 17 form univalent negative ions. Hence, when a group 1 element reacts with a group 17 element, a compound of the sort MX is formed. Hence, when a group 1 element reacts with bromine, a salt is formed with the general formula MBr.

Elements of group 1 are highly electro positive metals. They react with water to form the metal hydroxide and release hydrogen gas. Hence, when group 1 elements react with water, hydrogen gas is released.

A group 1 element forms a univalent positive ion while a group 16 element forms a divalent negative ion. Hence, when a groups 1 element reacts with oxygen, the compound formed must have the general formula M2O.

The reactivity of group 1 metal increases down the group hence Cs is the most reactive group 1 element.

Lithium displays a slightly different chemistry from other group 1 elements because of its small size.

Answer:

2. 181.25 K.

3. 0.04 atm.

Explanation:

2. Determination of the temperature.

Number of mole (n) = 2.1 moles

Pressure (P) = 1.25 atm

Volume (V) = 25 L

Gas constant (R) = 0.0821 atm.L/Kmol

Temperature (T) =?

The temperature can be obtained by using the ideal gas equation as illustrated below:

PV = nRT

1.25 × 25 = 2.1 × 0.0821 × T

31.25 = 0.17241 × T

Divide both side by 0.17241

T = 31.25 / 0.17241

T = 181.25 K

Thus, the temperature is 181.25 K.

3. Determination of the pressure.

Number of mole (n) = 10 moles

Volume (V) = 5000 L

Temperature (T) = –10 °C = –10 °C + 273 = 263 K

Gas constant (R) = 0.0821 atm.L/Kmol

Pressure (P) =?

The pressure can be obtained by using the ideal gas equation as illustrated below:

PV = nRT

P × 5000 = 10 × 0.0821 × 263

P × 5000 = 215.923

Divide both side by 5000

P = 215.923 / 5000

P = 0.04 atm

Thus, the pressure is 0.04 atm

Answer:

Valency is defined as the number of hydrogen atoms which combine directly or indirectly with one atom of an element.

Example:

One atom of nitrogen combines with three atoms of hydrogen to form ammonia gas. So, the valency of nitrogen is 3.

Answer:

0.0286M

Explanation:

Using the formula as follows:

CaVa = CbVb

Where;

Ca = concentration of HCl acid (M)

Cb = concentration of NaOH base (M)

Va = volume of HCl acid (mL)

Vb = volume of NaOH base (mL)

According to the information provided in this question;

Ca = 0.10 M

Cb = ?

Va = 10mL

Vb = 35mL

Using CaVa = CbVb

Cb = CaVa/Vb

Cb = (0.10 × 10) ÷ 35

Cb = 1 ÷ 35

Cb = 0.0286M

Answer:

it may also become impure,I think.

Answer:

A- 286.3L

Explanation:

Using the ideal gas law equation;

PV = nRT

Where;

P = pressure (atm)

V = volume (L)

n = number of moles (mol)

R = gas law constant (0.0821 Latm/molK)

T = temperature (K)

According to the information given in this question;

P = 1.14atm

V = ?

n = 15moles

T = 265K

Using PV = nRT

V = nRT ÷ P

V = (15 × 0.0821 × 265) ÷ (1.14)

V = 326.35 ÷ 1.14

V = 286.27 L

V = 286.3L

Answer:

Metilaminas

Explanation:

Las metilaminas a menudo están presentes en los tejidos corporales de organismos marinos como crustáceos, moluscos y en todos los peces marinos como N-óxido de trimetilamina, donde actúan para estabilizar la proteína que se desestabiliza por la presión y también se cree que actúa como un depresor del punto de congelación. en peces polares

Las metilaminas tienen olor a pescado podrido, basura o huevos podridos, de modo que una acumulación de metilamina en el cuerpo da como resultado la liberación de un olor a pescado en la amplitud, el sudor y la orina de un individuo

Answer:

is your answe b?

Explanation:

Im really asking

Answer:

aqueous solutions of silver nitrate and sodium chloride turn cloudy after mixing aqueous solutions of hydrochloric acid and sodium hydrogen carbonate produces bubbles on mixing Sodium hydroxide is mixed with water and the container feels warmer

Explanation:

A chemical change involves the formation of new substances. Also heat is absorbed or released in a chemical change. Another name for a chemical change is a chemical reaction.

In the first case, a reaction of the sort;

AgNO3(aq) + NaCl(aq) ---> AgCl(s) + NaNO3(aq)

The cloudy solution is due to the formation of AgCl precipitate.

In the second case, a reaction of the sort;

HCl(aq) + NaHCO3(aq) ---> NaCl(aq) + CO2(g) + H2O(l)

The gas evolved is due to the formation of CO2 in the process. Heat is also evolved showing that it is a chemical change.

Answer:

Both Arrhenius Base and Bronsted Lowry Base

Both Arrhenius Acid and Bronsted Lowry Acid

Arrhenius Acid Only

Arrhenius Base Only

Bronsted Lowry Acid Only

Bronsted Lowry Base Only

Explanation:

Answer:

Anhydrous calcium chloride  dissolves and becomes liquid

Anhydrous copper (ii) sulphate will produce crystal particles

Explanation:

Anhydrous calcium chloride is deliquescent and hence when it is exposed to air, it absorbs water from air. After absorbing water, it dissolves and after some time a pool of clear liquid appears.

Anhydrous copper (ii) sulphate will form crystal structures  and the following reaction will takes place

CuSO4 + 5 H20 --> CuSO4.5H2O

Answer:

All ionic compounds with alkali metals are soluble.

Explanation:

Certain elements always form soluble substances. Most of those elements are alkali metals/group 1 metals.

Answer:

22

Explanation:

3x4+  5x2

Answer:

b,,

Explanation:

tides are caused by the gravitational force of the sun and the moon

Uses of Diamond:

Uses of Diamond in Jewellery. They are used in jewellery (such as earrings, nose rings, engagement rings, pendants, etc.)

Uses of Diamond in Industry. Diamonds are used for industrial purpose.

Diamond in Beauty Products. Diamond in facial and diamond exfoliator is available these days.

Uses of Graphite:

Graphite is used in pencils and lubricants. It is a good conductor of heat and electricity. Its high conductivity makes it useful in electronic products such as electrodes, batteries, and solar panels.

Answer:

This statement is true.........

Answer:

i think true

Explanation:

Answer:

206°C

Explanation:

To solve this question we must use the combined gas law:

PV = nRT

Where P is pressure in atm, V is volume in liters, T absolute temperature, n are moles of gas, and R gas constant.

Pressure:

450kPa * (1atm / 101.325kPa) = 4.441atm

Volume:

658mL = 0.658L

Moles -Molar mass Ne: 20.1797g/mol-

1.50g * (1mol / 20.1797g) = 0.07433 moles

R: 0.082atmL/molK

Replacing to solve T:

T = PV/nR = 4.441atm*0.658L / 0.07433 moles*0.082atmL/molK =

T = 479K

In °C:

479K -273 =

Answer:

Explanation:

Ultimately, milk can be described as both. The actual description depends on the individual and/or company involved. For example, in many places milk if extracted from cows, bottled, and delivered to the end consumer. In this case, milk would be considered as natural because nothing has been done to change its nutritional composition. This changes when companies begin to pasteurise and homogenize the milk so that it has a longer shelf life and create different variations. The milk in this case no longer has the same nutritional composition and has been altered, and is therefore considered as processed.

Answer:

KNO3(s) K+(aq) + NO3-(aq)

Explanation:just did

The following reactions that would result in increased entropy is [tex]\rm KNO_3(s) -- > K+(aq) + NO_3^-(aq)[/tex]. The correct option is C.

Entropy of an object is the total amount of energy that is unavailable to do an amount of work.

It is a physical quantity that can be measure, it is the measure of arrangement of atoms.

Thus, the correct option is  C. [tex]\rm KNO_3(s) -- > K+(aq) + NO_3^-(aq)[/tex].

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Answer:

Zinc is reduced, The oxidation number of chlorine does not change, and Aluminum is oxidized.

Explanation:

Answer:

the answer is 1.1grams is the currect ans

According to the law of conservation of mass, 1.1 grams of calcium carbonate are formed  if 2.2 grams of CaO are used for this reaction.

According to law of conservation of mass, it is evident that mass is neither created nor destroyed rather it is restored at the end of a chemical reaction .

Law of conservation of mass and energy are related as mass and energy are directly proportional which is indicated by the equation E=mc².Concept of conservation of mass is widely used in field of chemistry, fluid dynamics.

Law needs to be modified in accordance with laws of quantum mechanics under the principle of mass and energy equivalence.This law was proposed by Antoine Lavoisier in the year 1789.If 56 g CaO gives 46.2 g calcium carbonate then  2.2 g CaO will give 2.2×46.2/56=1.1 g.

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