Solve these.. . . . .​

Answer:

An endothermic reaction is when heat is needed by the reaction, so it draws heat from its surroundings, making them feel cold. Just like a ice pack.

Answer:

a) clockwise

b) clockwise and

c) anticlockwise

Answer:

yes

Explanation:

because is smallest element that are made up of atom

Answer: Yes

Explanation:

Answer:

Pb3O4 + 4H2 → 3Pb + 4H2O

Explanation:

Pb3O4

Tritium - H2

Molar Mass of H2 Bond Polarity H-3 Hydrogen-3 3H T

Products

Lead - Pb

Molar Mass of Pb Plumbum Element 82 Bulk Lead

Water - H2O

Molar Mass of H2O Oxidation Numbers of H2O Dihydrogen Monoxide Dihydridooxygen Hoh Hydrogen Hydroxide Dihydrogen Oxide Oxidane Hydrogen Oxide Pure Water

Solution :

Cd(s) ---------------------->  [tex]Cd^{+2}[/tex] (aq) + 2[tex]e^-[/tex]      ,     [tex]E_0[/tex]  =   0.34 v

[tex]Cu^{+2}[/tex]  (aq)  +   2[tex]e^-[/tex]  ------------> Cu (s)             ,     [tex]E_0[/tex]  =  -0.04 v

----------------------------------------------------------------------------------------------

Cd(s)  +  [tex]Cu^{+2}[/tex]  (aq)  ------------->  [tex]Cd^{+2}[/tex] (aq)  +  Cu (s)   ,      [tex]E_0[/tex]  =  0.30 v  

The cell potential is defined as the measure of [tex]\text{ potential difference }[/tex]  between the [tex]\text{two half cells}[/tex] of an electrochemical cell.  

Explanation:

a unit of mass used to express atomic and molecular weights, equal to one twelfth of the mass of an atom of carbon-12.

Answer:

Atomic Mass Unit is also called Dalton. It is used to express atomic and molecular weight. It is defined as 1/12 of the mass of an unbound neutral atom of carbon.

Answer:

i think B is correct

Explanation:

Answer:

82 °C

Explanation:

Let the specific heat capacity of the coffee be that of water which is 4.2 J/g °C.

Now, at the final temperature, heat gained by Aluminum spoon ,Q equals heat lost by coffee, Q'.

Q = -Q'

Q = m₁c₁(T₂ - T₁) where m₁ = mass of aluminum spoon = 45 g, c₁ = specific heat of aluminum = 0.88 J/g °C, T₁ = initial temperature of aluminum spoon = 24 °C and T₂ = final temperature of aluminum spoon.

Q' = m₂c₂(T₂ - T₃) where m₂ = mass of coffee = 180 g, c₂ = specific heat of coffee = 4.2 J/g °C, T₃ = initial temperature of coffee = 85 °C and T₂ = final temperature of coffee.

So, Q = -Q'

m₁c₁(T₂ - T₁) = -m₂c₂(T₂ - T₃)

Making T₂ subject of the formula, we have

m₁c₁T₂ - m₁c₁T₁ = -m₂c₂T₂ + m₂c₂T₃

m₁c₁T₂ + m₂c₂T₂ =  m₂c₂T₃ + m₁c₁T₁

(m₁c₁ + m₂c₂)T₂ =  m₂c₂T₃ + m₁c₁T₁

T₂ =  (m₂c₂T₃ + m₁c₁T₁)/(m₁c₁ + m₂c₂)

substituting the values of the variables into the equation, we have

T₂ =  (180 g × 4.2 J/g °C × 85 °C + 45 g × 0.88 J/g °C × 24 °C )/(45 g × 0.88 J/g °C  + 180 g × 4.2 J/g °C)

T₂ =  (64260 J + 950.4 J)/(39.6 J/°C  + 756 J/°C)

T₂ =  65210.4 J/795.6 J/°C

T₂ =  81.96 °C

T₂ ≅  82 °C

Answer:

3 - a heterogeneous mixture

4- Sweet tea is an homogeneous mixture

Answer:

Explanation:

6. d

7. b

8. c

Answer:

DD

Explanation:

Answer:

v2 = u2 + 2as

it is the correct answer

Answer:

Between galaxies, retake the measurement.

Explanation:

Among both galaxies, reiterate the measurements. Instead of utilising a balloon, a scientist might create a model that shows in which everything really is and how cosmos is expanding rather than expanding. By inflating up the atmosphere to 1/2, 3/4, and full size, continue the operation.

Answer:

About bonding

Explanation:

A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. The bond may result from the electrostatic force of attraction between oppositely charged ions as in ionic bonds or through the sharing of electrons as in covalent bond.

Answer:

An ionic bond occurs between sodium and chlorine where sodium has one  electron while chlorine has seven electrons. The electron from sodium is lost and transferred to a chlorine atom which results in a sodium ion with a charge of one+ and a chloride ion with a charge of one-. These oppositely charged ions attract each other making a balanced charge to make a compound that is electrically neutral.. Sodium cation (Na+) and chlorine anion (Cl-) are attracted to each another to form sodium chloride (table salt). When dissolved in water, the sodium and chloride ions are strongly attracted to the polar water molecules because of ion-dipole interactions.  

Explanation:

the universe formed through the big bang explosion, all of the elements on Earth have been cooked for billions of years in stars and then released in the universe through super- nova explosions.

ayo thanks mate :0000000000000000000000

Answer:

2.76 gram

Explanation:

2AI + 6HCl → 2AlCl3 + 3H2

Answer

Al +2 HCl - AlCl2 + H2

Answer:

B. Lithium (Li) and iodine (1)

Explanation:

Ionic bond is a type of chemical bond that is formed between a metallic element and a non metallic element. The positive charge of the metallic ion is attracted to the negative charge of the non metallic ion to form an ionic bond.

According to the options given in this question, lithium and iodine will form an IONIC bond because lithium is a cation (+ve ion) while iodine is an anion (-ve).

Answer:

atom is electrically neutral because

the no.of protons is equal to no.of

electrons.

Therefore the negative charge and

positive charge cancels out.

Answer:

Not exactly such but Experimental manipulation describes the process by which researchers purposefully change, alter or influence the independent variables(IVs), which are also called treatment variables or factors in an experimental research design.

Answer:

Some examples of solutions are salt water, rubbing alcohol, and sugar dissolved in water. ... In our example of salt water, the solute is the salt. Solvent: this is the substance that makes up the majority of the solution. This is the part where the solute is dissolved.

Explanation:

I hope they should be right answer

Answer:

Radiometric dating or radioactive date is the method that uses radioisotope to date the formation of a rock. The age of the rocks will be determined.

Explanation:

Radioactive deterioration is a natural process and results from the unstable atomic core, which releases bits and parts.

These radioactive particles are released as (there are many types). This decline process results in a more equilibrated nucleus, which makes the atom stable when the number of protons and neutrons balances.

This radioactivity is suitable for dating, as a radioactive "parent" item is constantly decaying into a stable "daughter" element.

A single mineral grain or a whole rock may be dated. There are techniques by which the sample is excited in a nuclear reactor and then measured with a mass spectrometer. The isotope (such as in the argon-argon scheme).

Others put mineral grains under a special microscope, fir in the grains with an ionising laser beam that releases the mineral and the isotopes.

The isotopes are measured by a mass spectrometer inside the same machine (an example of this is SIMS analysis).

Isotopes are atoms of the same element that have different masses. The relative atomic mass (am) is a weighted average that takes into account the abundance of each isotope. We can calculate the relative atomic mass using the following expression.

[tex]am = \frac{\Sigma m_i \times ab_i}{100}[/tex]

where,

For Gallium,

[tex]70.59 amu = \frac{69 amu\ x + 71 amu\ y}{100}[/tex]     [1]

where "x" and "y" are the unknown abundances.

We also know that the sum of both abundances must be 100%.

x + y = 100

y = 100 - x   [2]

If we replace [2] in [1], we get

[tex]70.59 amu = \frac{69 amu\ x + 71 amu\ (100-x)}{100} \\7059 amu = -2 amu\ x + 7100amu \\x = 20.5[/tex]

Then, in [2]

y = 100 - x = 100 - 20.5 = 79.5

In conclusion, Ga-69 has an abundance of 20.5% and Ga-71 has an abundance of 79.5%.

You can learn more about isotopes in: https://brainly.com/question/21536220?referrer=searchResults

Answer:

B

Explanation:

strong acids ionize completely in water

Answer:

An acid that does not dissolve completely

Explanation:

Answer: C the “disappearance” of a small amount of mass.

Explanation:

Answer:

B

Explanation:

During the first half of the reaction there was an increase in the rate of reaction due to the high concentration of the reactants. But as the reaction continues we witness a decrease in the amount of reactants which lowers the rate.

Answer:

B.  The concentration of reactants decreased while the concentration of product increased.

Explanation:

took the test :)

Temperature is measured in Kelvin..