If 40.0 g of HCl react with an excess of magnesium metal, what is the theoretical yield of hydrogen?

Answers

Answer 1

Answer: The reaction between HCl and Mg is a substitution reaction:
2HCl + Mg --> MgCl2 + H2

The molar mass of HCl is 36.46 g/mol. Converting the amount of HCl,
40 g / 36.46 g/mol = 1.0971 mol

Based on the balanced chemical reaction, the stiochiometric ratio is:
2 mol HCl / 1 mol H2

So,
1.0971 mol HCl (1 mol H2 / 2 mol HCl) = 0.549 mol H2

Converting moles to mass
0.549 mol H2 (2.02 g H2 / mol H2) = 1.108 g H2

The theoretical yield is:
(1.108/40) (100) = 2.77

The yield is 2.77 g H2 per 100 g of HCl

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Where does the energy from the nuclear reaction go?

Answers

The energy fro the nuclear reaction go on to split other nearby atoms

I hope that's help !

Which of the following has the greatest number of atoms? a) 1.0 mol He b) 0.60 mol H2 c) 20 g Potassium d) 8.5 mL H2O (density of H2O = 1 g/mL) e) 22.6 g KMnO4

Answers

Answer:

The H2O sample has the greatest number of atoms. 1.41 moles, or (1.041 moles)*(5.023x10^23) atoms

Explanation:

We need to convert each value into moles, a count of the number of atoms/molecules.

a) 1.0 moles He

b) 0.60 moles H2

c) 20 grams K: convert to moles with the molar mass of K

(20 grams K)/(39.1 g/mole K) = 0.511 moles K

d) 8.5 mL H2O (density of H2O = 1 g/mL).

Find the mass of the H2): (8.5 ml)*(1 g/ml) = 8.5 grams H2)

Now calculate moles H2): (8.5 grams)/(18 grams/mole) = 0.473 moles H2O

e) 22.6 g KMnO4

(22.6 g KMnO4 )*(158.0 g/mole) = 0.143 moles

Now we need to take into account the number of atoms per molecule:

Molecule Atoms/Molecule Moles Atoms(moles)

He 1 1.0 1.0

H2 2 0.60 1.2

K 1 0.51 0.51

H2O 3 0.47 1.41

KMnO4 6 0.143 0.86

The H2O sample has the greatest number of atoms. 1.41 moles, or (1.041 moles)*(5.023x10^23) atoms

Is there a pattern in how one can predict how many covalent bonds an atom will form?

Answers

Answer:

In molecules, there is a pattern to the number of covalent bonds that different atoms can form. Each block with a number indicates the number of covalent bonds formed by that atom in neutral compound

Explanation:

I don't really know the answer sorry

An element X has two isotopes. X–15 has 7 protons and 8 neutrons. Determine the atomic number and mass number of the second isotope, which has 10 neutrons in its nucleus. a. atomic number = 8; mass number = 9
b. atomic number = 8; mass number = 17
c. atomic number = 7; mass number = 17
d. atomic number = 7; mass number = 15

Answers

c. Atomic number = 7; mass number = 17

The atomic number of the first isotope is 7.

Isotopes of the same element have the same atomic number, so the atomic number of the second isotope must also be 7.

Mass number = no. of protons + no. of neutrons, or

A = p + n

∴ A = 7 + 10 = 17

Options “a.” and “b.” have the wrong atomic numbers, and option “d.” has the wrong mass number.

Answer:

Explanation:

How would you solve this problem??

Answers

Calculate the pOH where [OH⁻]=4.7×10⁻³M:
pOH=-log[OH⁻]
pOH=-log(4.7×10⁻³)
pOH=2.33

Calculate [OH⁻] if the pOH is 1.34:
pOH=-log[OH⁻]
10^(-pOH)=[OH⁻]
[OH⁻]=10^(-pOH)
[OH⁻]=10^(-1.34)
[OH-]=0.0457M or [OH⁻]=4.57×10⁻²M

Calculate pH if the [OH⁻] is 1.74×10⁻²M:
[H⁺]=K(w)/[OH⁻] or pOH=-log[OH⁻]
[H⁺]=(1×10⁻¹⁴)/(1.57×10⁻²) pOH=-log(1.74×10⁻²)
[H⁺]=6.369×10⁻¹³M pOH=1.759
pH=-log[H⁺] pH=14-pOH
pH=-log(6.369×10⁻¹³) pH=14-1.759
pH=12.2 pH=12.2

I hope this helps. Let me know if anything is unclear.

Within a particular compound, an atom gives up two electrons. This atom is A. part of a covalent compound.
B. positively charged.
C. negatively charged.
D. not part of an electrolyte.

Answers

Answer:

The correct answer is option B. positively charged.

Explanation:

A positively charged ion is an atom that readily loses its one or more electrons in a compound. Positively charged ion generally has same number of electrons and protons which means they are neutral charge atom. These atoms are generally attracted to negatively charged ion that lack electron in outer shell.

Thus, the correct answer is option. B. positively charged.

It is a positively charges because when an atom gives up electrons it becomes positively charges. Think of it like this.....its being generous so it deserves to be a positive person. ;D.
It cant be A. because a covalent bond only shares and doesn't give up electrons. Our answer must be an ion.
Its not negatively charged because it didn't gain any.

So our answer is B. positively charged

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Plz I need help is the 2nd time I post this

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