Giving brainiest to whoever answers correctly.

How to I find the number of electrons in and Atom?

Inessa [10]

Look at the atomic number of an element on the periodic table which is the smaller number.
The atomic number shows the number of protons/electrons so the number of protons and electrons are the same.
Whereas the mass number of an element (the other number) is the number of protons + neutrons.

8 0

3 years ago

I NEED HELP PLEASE, THANKS! :)

krok68 [10]

Answer:

$\large \boxed{\text{2.20 g Pb}}$

Explanation:

They gave us the masses of two reactants and asked us to determine the mass of the product.

This looks like a limiting reactant problem.

1. Assemble the information

We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.

Mᵣ: 239.27 32.00 207.2

2PbS + 3O₂ ⟶ 2Pb + 2SO₃

m/g: 2.54 1.88

2. Calculate the moles of each reactant

$\text{Moles of PbS} = \text{2.54 g PbS } \times \dfrac{\text{1 mol PbS}}{\text{239.27 g PbS}} = \text{0.010 62 mol PbS}\\\\\text{Moles of O}_{2} = \text{1.88 g O}_{2} \times \dfrac{\text{1 mol O}_{2}}{\text{32.00 g O}_{2}} = \text{0.058 75 mol O}_{2}$

3. Calculate the moles of Pb from each reactant

$\textbf{From PbS:}\\\text{Moles of Pb} = \text{0.010 62 mol PbS} \times \dfrac{\text{2 mol Pb}}{\text{2 mol PbS}} = \text{0.010 62 mol Pb}\\\\\textbf{From O}_{2}:\\\text{Moles of Pb} =\text{0.058 75 mol O}_{2} \times \dfrac{\text{2 mol Pb}}{\text{3 mol O}_{2}}= \text{0.039 17 mol Pb}\\\\\text{PbS is the $\textbf{limiting reactant}$ because it gives fewer moles of Pb}$

4. Calculate the mass of Pb

$\text{ Mass of Pb} = \text{0.010 62 mol Pb} \times \dfrac{\text{207.2 g Pb}}{\text{1 mol Pb}} = \textbf{2.20 g Pb}\\\\\text{The reaction produces $\large \boxed{\textbf{2.20 g Pb}}$}$

5 0

3 years ago

Cyanogen, (CN)₂, has been observed in the atmosphere of Titan, Saturn’s largest moon, and in the gases of interstellar nebulas.

zhuklara [117]

The enthalpy of formation of CF $4$ is -678.82 kJ/mol.

<h3>What is enthalpy ?</h3>

A thermodynamic system's enthalpy H is calculated by multiplying its internal energy by the product of its pressure and volume. In the equation H = U + pV, U stands for internal energy, p for pressure, and V for system volume; pV is also frequently referred to as the pressure energy P.

The amount of heat in a system under constant pressure is measured as enthalpy (H). Chemists frequently gauge how the enthalpy of chemical systems changes when reactants transform into products. The enthalpy change, which is the same thing as the heat that is absorbed or released by a process at constant pressure, is denoted by the letter H.

To learn more about enthalpy from the given link:

brainly.com/question/3393755

#SPJ4

7 0

1 year ago

Did the subscripts (the little numbers<br>

olga_2 [115]

Hey, you didn’t finish your answer!
Can you finish it so I can help you? Thanks!

4 0

3 years ago

What physical and chemical properties would an antique dealer use to determine the substance that makes up a

Alja [10]

Answer:

Characteristics such as melting point, boiling point, density, solubility, color, odor, etc. are physical properties. Properties that describe how a substance changes identity to produce a new substance are chemical properties. ... Physical and chemical properties can be used to classify a substance as ionic or molecular.

8 0

2 years ago