All categories

2 years ago

How many protons do atoms of lead have?

Chemistry

1 answer:

Dahasolnce [82]2 years ago

4 0

Answer: exactly 82 protons

Explanation:

Since lead has 82 protons the number of neutrons in an atom of lead-204 is 204-82=122. Similarly, lead-206 has 124 neutrons, lead-207 has 125 neutrons and lead-208 has 126 neutrons.

You welcome :)

You might be interested in

Which of the following IS a valid piece scientific evidence?

Vanyuwa [196]

im sorry it doesn't show

5 0

3 years ago

a book with a mass of 1 kg is dropped from a height of 3 m. what is the potential energy of the book when it reaches the floor?

mafiozo [28]

Well, first of all, the formula for finding potential energy is;
PE=mgh
Where; m is the mass
g is the gravitational force or acceleration due to gravity
h is the height.
Anyway, according to the question, the mass is 1kg, the acceleration due to gravity has a constant value of 10ms² . And the height is 3m. Now you just have to use all these in the formula. So;
mgh= 1 x 10 x 3. That will be 30. And the unit of potential energy is Joule. So the answer is 30 joules. Hope i helped. Have a nice day.

5 0

3 years ago

How many moles of aluminum oxide (Al2O3) can be produced from 12.8 moles of oxygen gas (02)

zhannawk [14.2K]

Answer:

Theoretical Yield

Percent yield

Example stoichiometry problem

How much oxygen can be prepared from 12.25 g KClO3 . (Use molar mass KClO3 = 122.5 g.)

Most stoichiometry problems can be solved using the following steps.

Step 1.

Write and balance the equation for the decomposition of KClO3 with heat (∆). 2KClO3 + ∆ → 2KCl + 3O2

Step 2.

Convert what you have (in this case g KClO3) to moles.

# moles = grams/molar mass = 12.25 g /122.5 = 0.100 mole KClO3.

Step 3.

Using the coefficients in the balanced equation, convert moles of what you have (moles KClO3) to moles of what you want (in this case moles oxygen).

0.100 mol KClO3 x (3 moles O2/2 moles KClO3) = 0.100 x (3/2) = 0.150 mole O2.

Step 4.

Convert moles from step 3 to grams.

moles x molar mass = grams

0.150 mole O2 x (32.0 g O2/mole O2) = 4.80 g O2 produced from 12.25 g KClO3. This is the theoretical yield. If the ACTUAL yield is 4.20 grams, calculate percent yield. Percent yield = (actual yield/theoretical yield) x 100 = (4.20/4.80) x 100 = 87.5% yield

NOTE: In step 1, moles can be obtained other ways; in step 4 moles can be converted to other units.

a. For solutions, M x L = moles (or mL x M = millimoles).

b. For gases, L/22.4 = moles

4 0

3 years ago

onsider the reaction, NO2(g) + CO(g) → NO(g) + CO2(g), for which the rate law has been determined to be: Rate = k[NO2]2[CO]. Whi

nlexa [21]

Answer:

The correct answer is option D.

Explanation:

Rate of the reaction is a change in the concentration of any one of the reactant or product per unit time.

$NO_2(g) + CO(g)\rightarrow NO(g) + CO_2(g)$

Rate of the reaction:

$R=-\frac{1}{1}\times \frac{d[NO_2]}{dt}=-\frac{1}{1}\times \frac{d[CO]}{dt}$

Rate of decrease in nitrogen dioxide concentration is equal to the rate of decrease in carbon monoxide.

Given rate expression of the reaction:

$R = k[NO2]^2[CO]$

Rate of the reaction on doubling concentration of nitrogen dioxide and carbon monoxide : R'

$R'=k(2\times [NO_2])^2(2\times [CO])=8\times k[NO2]^2[CO]=8R$

Doubling the concentrations of nitrogen dioxide and carbon monoxide simultaneously will increase the rate of the reaction by a factor of eight.

Hence, none of the given statements are true.

6 0

3 years ago

Read 2 more answers

Most reactions speed up when

miss Akunina [59]

For a reaction to occur, there should be mobility of ions in reactant side.
If the reactant is larger, its mobility will be lesser than that of smaller ones.
So reactants smaller in size have higher mobility which makes reaction faster.

Hence D is the correct option.

Hope this helps, have a great day/night ahead!

7 0

3 years ago

Read 2 more answers