A student determines the calcium content of a solution by first precipitating it as calcium hydroxide, and then decomposing the hydroxide to calcium oxide by heating. How many grams of calcium oxide should the student obtain if his solution contains 55.0 mL of 0.458 M calcium nitrate?

Answer:

Weight = mass × gravitational

Weight = 60 kg × 9.8 ms²

= 588 N

Explanation:

hope it helps

Weight of the boy = Mass of the boy × g

= 60 × 9.8

= 588kgm/s²

= 588N

Answer: The statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.

Explanation:

A strong acid upon dissociation gives a weak conjugate base. This can also be said as stronger is the acid, weaker will be its conjugate base or vice-versa.

Hydrofluoric acid is a strong base as it dissociates completely when dissolved in water.

For example, [tex]HF \rightleftharpoons H^{+} + F^{-}[/tex]

The conjugate base is [tex]F^{-}[/tex] which is a weak base.

Acetic acid is a weak acid as it dissociates partially when dissolved in water. So, the conjugate base of acetic acid is a strong base.

[tex]CH_{3}COOH \rightarrow CH_{3}COO^{-} + H^{+}[/tex]

Thus, we can conclude that the statement conjugate base of hydrofluoric acid is weaker than that of acetic acid is most likely true.

Answer:

λ = 2.38 × 10^(-7) m

Explanation:

We are given the work function for palladium as 503.7 kJ/mol.

Now let's convert this to KJ/electron.

We know from avogadro's number that;

1 mole of electron = 6.022 × 10^(23) electrons

Thus,

503.7 kJ/mol = 503.7 × 1/(6.022 × 10^(23)) = 8.364 × 10^(-22) KJ/electron = 8.364 × 10^(-19) J/electron

Formula for energy of a photon is;

E = hv

Where;

h is Planck's constant = 6.626 × 10^(-34) J.s

v is velocity

Now, v = c/λ

Where;

c is speed of light = 3 × 10^(8) m/s

λ is wavelength of light.

Thus;

E = hc/λ

Making λ the subject, we have;

λ = hc/E

λ = (6.626 × 10^(-34) × 3 × 10^(8))/(8.364 × 10^(-19))

λ = 2.38 × 10^(-7) m

Answer:

D

Explanation:

The first ionization energy is the minimum energy required to remove the most loosely bound electron from an atom.

Good luck!

19. moth balls in the closet and observe after several days.

20. whenever wax or a candle burns it turns from solid to liquid but again at room temperature it turns to solid

21. evaporation, condensation, precipitation

22. it produces new substances

23. vinegar Bubbles when baking soda is added

24. steam

Answer:

Explanation:

Because you only have one repeat unit, n=1. 2n-1 becomes 2(1)-1 which is equal to one, meaning one molecule of H2O is produced, as is shown by the top condensation polymerisation reaction.

If you had two repeat units, n=2 so 2n-1=3. Three H2O molecules are produced because you would need two molecules of each reactant so three condesation reactions would occur and three molecules of H2O would be released.

Answer: Because when you blow air /gas into a balloon you fill it with air particles ,so they more you blow u blow in more air particles so they tend to collide with each other ,so as they hit the walls of the balloons pressure is exerted ,so the pressure keeps the balloon inflated with its shape

Answer:

isotope 2

Explanation:

it has the highest percentage abundance

Answer:

Explanation:

If a substance contains ionic bonds, then it’s properties would include high melting and boiling points, a crystalline structure, the ability to dissolve quite easily in water, the ability to conduct electricity, have good insulation and lastly be quite hard and brittle.

If my answer was helpful, would you consider giving me a “Brainliest”?. Thank you :)

Answer:

The average atomic mass includes all of the isotopes of that atom which exist in nature. Almost all elements have at least two isotopes which naturally occur. Recall that isotopes are atoms with the same atomic number (protons), but a different number of neutrons.

Answer:

Explanation:

Una manifestación, protesta o marcha es la exhibición pública de la opinión de un grupo activista (económica, política o social), mediante una congregación en las calles, a menudo en un lugar o una fecha simbólicos y asociados con esa opinión.

Answer:

D. Burning a peice of wood

Explanation:

Because when you burn wood a chemical reaction happenes between the flames and the wood making the wood into ashes.

Hope this helps you :)

The dissolving salt in water is an an example of a chemical change. The correct option is A.

A chemical change, also known as a chemical reaction, is the production of new substances with changing chemical compositions and characteristics.

In water, sodium chloride dissociates into Na+ ions and Cl- ions, which may be described as a chemical process.

The ionic connections between the atoms are broken as salt dissolves. Because the reactant (sodium chloride or NaCl) varies from the products (sodium and chloride ions), a chemical reaction takes place.

Thus, the correct option is A.

For more details regarding chemical change, visit:

https://brainly.com/question/23693316

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Answer:

1. Isotope with mass number 39.

2. 39.02g/mol

Explanation:

1. The most common isotope is the isotope in the higher proportion, that is:

Isotope with mass number 39.

2. The average atomic mass is the sum of the masses times their abundance. For the element X:

Average atomic mass:

38*0.0967 + 39*0.7868 + 40*0.1134 + 41*0.0031

= 39.02g/mol

Answer:

Similar charges seek to be the maximum distance possible from each other

Explanation:

On a charged sphere, there are like charges and these like charges are repelled by each other to the far ends of the sphere. Hence they are distributed uniformly in the sphere.

Answer:

39.02

Explanation:

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

Isotope A:

Mass of A = 38

Abundance of A (A%) = 9.67%

Isotope B:

Mass of B = 39

Abundance of B (B%) = 78.68%

Isotope C:

Mass of C = 40

Abundance of C (C%) = 11.34%

Isotope D:

Mass of D = 41

Abundance of D (D%) = 0.31%

Average atomic mass of X =?

The average atomic mass of X can be obtained as follow:

Average = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100] + [(Mass of D × D%)/100]

= [(38 × 9.67)/100] + [(39 × 78.68)/100] + [(40 × 11.34)/100] + [(41 × 0.31)/100]

= 3.6746 + 30.6852 + 4.536 + 0.1271

= 30.02

Thus, the average atomic mass of X is 39.02

Answer:

a. H + d. Na

Explanation:

This is Mixture of H and Na. Because of H and in the emission and Absorption spectrum of H Total 5 lines [Red, Green, Blue and Purple (2)) are present and in the spectrum of Na Two yellow lines are present. In the mixture all this lines are are also 5 + Present. Total lines are 5+2= 7 (H+ Na)

Therefore, the answer is a. H + d. Na

Answer:

Molecular mass, M = 58.20 g/mol.

Explanation:

Given the following data;

Conversion:

760 mmHg = 1 atm

770 mmHg = 770/760 = 1.0131 atm

Temperature = 25°C = 273 + 25 = 298 K

To find the molecular mass, we would use the ideal gas law equation (density version);

PM = dRT

Where;

Making M the subject of formula, we have;

[tex] M = \frac {dRT}{P} [/tex]

Substituting into the formula, we have;

[tex] M = \frac {2.41 * 0.0821 * 298}{1.0131} [/tex]

[tex] M = \frac {58.9626}{1.0131} [/tex]

Molecular mass, M = 58.20 g/mol.

Answer : Metal containers are not used for storing acid because most of the time acid reacts with almost every metal and produces salts or oxides which alters the acid characteristics making it useless .......

Answer:xl/ck xLKsx

Explanation:sl/cs c/ls

Answer:

-2,802.960 kJ

Explanation:

The dimensional equation of the given quantities is presented as follows;

(6 mol) × (-393.5 kJ/mol) + (6 mol) × (-285.83 kJ/mol) - (1 mol) × (-1,273.02 kJ/mol) = ? kJ

The equation, can be written as follows;

[tex]\left (6 \times (-393.5) \, mol \times \dfrac{kJ}{mol} \right ) + \left(6 \times (-285.83) \, mol \times \dfrac{kJ}{mol} \right) - \left (1 \times (-1,273.02) \, mol \times \dfrac{kJ}{mol} \right) = ?[/tex]We note that [tex]mol \times \dfrac{kJ}{mol} \right) = kJ[/tex], therefore, the above equation becomes;

[tex]\left (6 \times (-393.5) \ kJ\right ) + \left(6 \times (-285.83) \ kJ \right) - \left (1 \, \times (-1,273.02) \ kJ \right) = -2,802.960 kJ[/tex]

Answer:

C. ((6 mol)(-393.5 kJ/mol) + (6 mol)(-285.83 kJ/mol)) - (1 mol)(-1,273.02 kJ/mol)

Explanation:

Got it right on edge.
: the one after is -2803.

Answer:

Answer:

3.36×10²⁶ g

Explanation:

Molar mass ( O2) = 32g/mol

mole(O2) = 1.05×10²⁵mol

Mass(O2) = ?

mole(n)= mass(m)/Molar mass(M)

n×M = m

1.05×10²⁵ mol × 32g/mol = mass

mass= 3.36×10²⁶ g

Answer:

i believe energy is your answer here

Answer:

I think option two (2) is the correct answer

here's your answer hope this will help

Answer:

2.8 L

Explanation:

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

Number of mole (n) = 0.109 mole

Pressure (P) = 0.98 atm

Temperature (T) = 307 K

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

Volume (V) =?

The volume of the helium gas can be obtained by using the ideal gas equation as follow:

PV = nRT

0.98 × V = 0.109 × 0.0821 × 307

0.98 × V = 2.7473123

Divide both side by 0.98

V = 2.7473123 / 0.98

V = 2.8 L

Thus, the volume of the helium gas is 2.8 L.