Which statement is TRUE about enzymes?

Which of these is an isoelectronic series? question 7 options: 1) na+, k+, rb+, cs+ 2) k+, ca2+, ar, s2– 3) na+, mg2+, s2–, cl–

-BARSIC- [3]

An isoelectronic series is where all of the ions listed have the same number of electrons in their atoms. When an atom has net charge of zero or neutral, it has equal number of protons and electrons. Hence, it means that the atomic number = no. of protons = no. of electrons. If these atoms become ions, they gain a net charge of + or -. Positive ions are cations. This means that they readily GIVE UP electrons, whereas negative ions (anions) readily ACCEPT electrons. So, to know which of these are isoelectronic, let's establish first the number of electron in a neutral atom from the periodic table:

Na=11; K=19; Rb=37; Cs = 55; Ca=20; S=16; Mg=12; Li=3; Be=4; B=5; C=6, Ar = 18

A. Na⁺: 11-1 = 10 electrons
K⁺: 19 - 1 = 18 electrons
Rb⁺: 37-1 = 36 electrons

B. K⁺: 19 - 1 = 18 electrons
Ca²⁺: 20 - 2 = 18 electrons
Ar: 18 electrons
S²⁻: 16 +2 = 18 electrons

C. Na⁺: 11-1 = 10 electrons
Mg²⁺: 12 - 2 = 10 electrons
S²⁻: 16 +2 = 18 electrons

D. Li=3 electrons
Be=4 electrons
B=5 electrons
C=6 electrons

The answer is letter B.

6 0

3 years ago

Explain why this reaction can be classified as a synthesis reaction

rusak2 [61]

The reason why the reaction written on the picture can be classified as a synthesis reaction is :
the reaction shows one compound that formed from two compounds

hope this helps

5 0

3 years ago

Gaseous methane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water . Suppose 7.9 g of methane is

Vikki [24]

Explanation:

The given reaction is as follows.

$CH_{4} + 2O_{2} \rightarrow CO_{2} + 2H_{2}O$

As it is known that number of moles equal mass divided by molar mass. Molar mass of methane is 16 g/mol.

Hence, No. of moles = $\frac{mass}{molar mass}$

= $\frac{7.9 g}{16 g/mol}$

= 0.493 mol

Molar mass of oxygen is 32 g/mol.

Hence, its number of moles = $\frac{mass}{molar mass}$

= $\frac{14.4 g}{32 g/mol}$

= 0.45 mol

As, it is shown from the reaction that 1 mole of methane needs 2 mole of oxygen.

Therefore, 0.493 mol of methane needs $2 \times 0.45 mol$ equals 0.9 moles of oxygen.

As there is only 0.45 moles of oxygen for the reaction. So, it means that oxygen is the limiting reagent.

Hence, for 0.45 moles of oxygen, methane required is as follows.

$\frac{0.45}{2}$ = 0.225 moles

So, 0.225 moles of methane is equal to $0.225 \times 16$ = 3.6 g

As, 3.6 g of methane reacts with oxygen. Therefore, amount of methane remains is calculated as follows.

(7.9 g - 3.6 g) = 4.3 g

Thus, we can conclude that the minimum mass of methane that could be left over by the chemical reaction is 4.3 g.

8 0

3 years ago

What is the molar mass of CH2O2?

Flauer [41]

M CH₂O₂:
mC + mH×2 + mO₂×2 = 12g + 1g×2 + 16g×2 = 46g/mol

:)

5 0

3 years ago

Read 2 more answers

When comparing certain amino acid sequences in the protein hemoglobin of humans to those of other animals, scientists found that

asambeis [7]

Answer:

Explanation:

animal having amino acid sequence most similar to man's will be closely related . The difference between types of amino acid in hemoglobin of baboon and man is seven , between dog and man is ten , between gorilla and man is one and between lemur and man is eight . So difference is least in case of gorilla. So gorilla is supposed to be closest to man in ancestry.

4 0

4 years ago