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3 years ago

Calculate the number of atoms in 3mol helium

1 answer:

7 0

<span>The chemical formula of Helium is He.

Question 1 :

Given n = 1.11 x 10^-6

To get no. of the particle,
No of particle = no. of mole x Avogadro Constant
p = n x NA

1 mol of Helium = 6.02 x 10^23

No of atoms = (6.02 x 10^23) x (1.11 x 10^-6)
= 6.66 x 10^17

................................

Question 2 :

Given p = 4.29x10^21

p = n x NA
4.29 x 10^21 = n x (6.02 x 10^23)
(4.29 x 10^21) / (6.02 x 10^23) = n
n = Approximately 7.126 x 10^-3

Hope the answer is right :)</span>

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Calculate the mass percent for all components in a solution containing the following. 0.350 Kg of water, 5.4 moles of ammonia an

Alina [70]

Answer:

% Water = 54.96%

% Ammonia = 0.14%

% Cobalt (II) Nitrate = 30.62%

Explanation:

To calculate mass percent, first we need to <u>calculate the total mass of the mixture</u>:

Mass Water ⇒ 0.350 kg Water = 350 g water

Mass Ammonia⇒We use ammonia's molar mass⇒5.4 mol * 17 g/mol = 91.8 g

Mass cobalt (II) nitrate ⇒ 195.0 g

Total Mass = Mass Water + Mass Ammonia + Mass Cobalt Nitrate

Total Mass = 350 g+ 91.8 g+ 195 g = 636.8 g

To calculate each component's mass percent, we divide its mass by the total mass and multiply by 100:

% Water ⇒ 350/636.8 * 100% = 54.96%

% Ammonia ⇒ 91.8/636.8 * 100% = 0.14%

% Cobalt (II) Nitrate ⇒ 195/636.8 * 100% = 30.62%

8 0

3 years ago

Use Table 1: Analysis of Decay in the laboratory guide to answer this question: Scientists find a piece of wood that is thought

Sladkaya [172]

<span>We are given the initial amount of 1 million carbon-14 atoms and the final amount which is 1/16 of the current atmospheric 14C levels. Also, the half life of carbon is </span>5,750 years. WE can use the decay formula

Aₓ = A₀e^-(ln2/t1/2)t
1,000,000(1/16) = (1,000,000)e^-(ln2/5750)t
t = 23,000 years

6 0

3 years ago

Technetium (Tc; Z = 43) is a synthetic element used as a radioactive tracer in medical studies. A Tc atom emits a beta particle

Sedaia [141]

Question in incomplete, complete question is:

Technetium (Tc; Z = 43) is a synthetic element used as a radioactive tracer in medical studies. A Tc atom emits a beta particle (electron) with a kinetic energy (Ek) of $4.71\times 10^{-15}J$ . What is the de Broglie wavelength of this electron (Ek = ½mv²)?

Answer:

$6.762\times 10^{-12} m$ is the de Broglie wavelength of this electron.

Explanation:

To calculate the wavelength of a particle, we use the equation given by De-Broglie's wavelength, which is:

$\lambda=\frac{h}{\sqrt{2mE_k}}$

where,

= De-Broglie's wavelength = ?

h = Planck's constant = $6.624\times 10^{-34}Js$

m = mass of beta particle = $9.1094\times 10^{-31} kg$

$E_k$ = kinetic energy of the particle = $4.71\times 10^{-15}J$

Putting values in above equation, we get:

$\lambda =\frac{6.624\times 10^{-34}Js}{\sqrt{2\times 9.1094\times 10^{-31} kg\times 4.71\times 10^{-15}J}}$

$\lambda = 6.762\times 10^{-12} m$

$6.762\times 10^{-12} m$ is the de Broglie wavelength of this electron.

3 0

3 years ago

I need help with this one pls, ty! ASAP

LuckyWell [14K]

Answer:

Explanation:

1. A measure of how quickly velocity is changing is the acceleration

Acceleration is the rate of change of velocity with time. The rate at which a body is changing its velocity is known as the acceleration.

It is measured in the unit m/s²

2. Speed in a given direction is the velocity

Velocity is a vector quantity which measures the magnitude of motion in a specific direction. It is simply speed in a given direction.

When we say a motorcycle travels at the rate of 5m/s due east, we are describing the velocity of such body.

3. Force that resists moving one object against another is the friction

Friction is a force that opposes motion. It prevents a body from moving.

4. Measure of the pull of gravity on an object Weight

Weight is a measure of the amount of gravitational force on a body. It is mathematically expressed as;

W = mg

W is the weight, m is the mass and g is the acceleration due to gravity

5 Tendency of an object to resist a change in motion is inertia

Inertia is the tendency of body to resist change in motion. It is the ability of a body to remain in a perpetual state of rest.

6 Size is the magnitude

4 0

2 years ago

How many atoms are there in 7.80 moles of germanium

Orlov [11]

<h3>Answer:</h3>

4.70 × 10²⁴ atoms Ge

<h3>General Formulas and Concepts:</h3>

<u>Math</u>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

<u>Chemistry</u>

<u>Atomic Structure</u>

Using Dimensional Analysis
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

<h3>Explanation:</h3>

<u>Step 1: Define</u>

7.80 mol Ge

<u>Step 2: Identify Conversions</u>

Avogadro's Number

<u>Step 3: Convert</u>

$\displaystyle 7.80 \ mol \ Ge(\frac{6.022 \cdot 10^{23} \ atoms \ Ge}{1 \ mol \ Ge} )$ = 4.69716 × 10²⁴ atoms Ge

<u>Step 4: Check</u>

<em>We are given 3 sig figs. Follow sig fig rules and round.</em>

4.69716 × 10²⁴ atoms Ge ≈ 4.70 × 10²⁴ atoms Ge

8 0

2 years ago