How many oxygen atoms in 2.28 mol HNO3 ?

Which of the following statements regarding alpha particles are true? Check all that apply.a. Alpha particles have a mass number

egoroff_w [7]

Answer:

The only true statement is:

a. Alpha particles have a mass number of 4

Explanation:

Alpha particles are radiactive particles equivalent to a helium nucleus, so they have two protons and two neutrons.

Hence, alpha particles, α, are represented as:

⁴₂He

The superscript 4 to the left of the chemical symbol is the mass number: 2 protons + 2 neutrons = 4

The subscript 2 to the left of the chemical symbol is the atomic number: 2 protons = 2.

Hence, the statement "a. Alpha particles have a mass number of 4" is true.

As for the other statements, you have:

b. Alpha particles have a nulear charge of +1: false

Since, these particles are the nucleous of the helium atom, the nuclear charge equals the number of protons of this atom: +2. Hence, the statement is false.

c. Alpha particle formation is accompanied by the conversion of a proton into a neutron and d. Alpha particle formation is accompanied by the conversion of a neutron into a proton. (both false)

The conversion of a protons into a neutrons and the conversion of a neutron into a proton are product of other kind of radiactive desintegrations.

The conversion of a proton into a neutron involves the emission of a positron ( particle with same mass as the electron but positive charge) from the nucleus, which is represented as ⁰₊₁β.

The conversion of a neutron into a proton involves the emssion of an electron from the nucleus, which is the emission of a beta particle represented as ⁰₋₁β.

Therefore, these last two statements are also false.

4 0

3 years ago

The activation energy of a certain uncatalyzed reaction is 64 kJ/mol. In the presence of a catalyst, the Ea is 55 kJ/mol. How ma

Ksivusya [100]

Answer:

About 5 times faster.

Explanation:

Hello,

In this case, since the Arrhenius equation is considered for both the catalyzed reaction (1) and the uncatalized reaction (2), one determines the relationship between them as follows:

$\frac{k_1}{k_2}=\frac{Aexp(-\frac{Ea_1}{RT} )}{Aexp(-\frac{Ea_2}{RT})} \\\frac{k_1}{k_2}=\frac{exp(-\frac{Ea_1}{RT} )}{exp(-\frac{Ea_2}{RT})}$

By replacing the corresponding values we obtain:

$\frac{k_1}{k_2}=\frac{exp(-\frac{55000J/mol}{8.314J/molK*673.15K} )}{exp(-\frac{64000J/mol}{8.314J/molK*673.15K} )} =4.8$

Such result means that the catalyzed reaction is about five times faster than the uncatalyzed reaction.

Best regards.

4 0

3 years ago

Sucrose, a major product of photosynthesis in green leaves, is synthesized by a battery of enzymes. The substrates for sucrose s

Gwar [14]

Answer:

Sucrose is a disaccharide composed of alpha D gluose and beta D fructose linked together by beta 2,alpha1 glycosidic linkage.

Explanation:

The specificity of glycosidic linkage very much essential to choose the substrate for the synthesis of specific disaccharide.

For example sucrose contain beta 2,alpha1 glycosidic linkage that means the hydroxyl group of anomeric carbon of one monosaccharide(fructose) should remain in beta conformation and the hydroxyl group of other monosaccharide(glucose) should remain in alpha conformation.

5 0

3 years ago

Which of the four macromolecules are the largest

Kruka [31]

Lipid you can look up the chemical structures and lipids are the longest which make them the largest

5 0

2 years ago

How many phosphorous atoms are found in three molecules of magnesium phosphate, 3Mg3(PO4)2?

aleksandr82 [10.1K]

Answer: Option (d) is the correct answer.

Explanation:

Since the given formula is $3Mg_{3}(PO_{4})_{2}$ . According to cross method formula, magnesium has +2 charge so, $PO_{4}$ is multiplied by 2.

Thus, 1 molecule of magnesium phosphate will contain 2 atoms of phosphorus.

Therefore, three molecules of magnesium phosphate contains following number of atoms.

Mg = 9

P = 6

O = 24

Hence, we can conclude that there are 6 atoms of phosphorus in three molecules of magnesium phosphate, $3Mg_{3}(PO_{4})_{2}$ .

4 0

3 years ago