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3 years ago

How many moless is 4.91x10^22 molecules of H3PO4?

1 answer:

6 0

1 mol = 6.023x10^23 number of molecules (Avogadro's number)

1 : 6.023x10^23
X : 4.91x10^22

(6.023x10^23)X = 4.91x10^22

X = 4.91x10^22/6.023x10^23

X = 0.082 Moles

You might be interested in

Which of the following statements regarding alpha particles are true? Check all that apply.a. Alpha particles have a mass number

egoroff_w [7]

Answer:

The only true statement is:

a. Alpha particles have a mass number of 4

Explanation:

Alpha particles are radiactive particles equivalent to a helium nucleus, so they have two protons and two neutrons.

Hence, alpha particles, α, are represented as:

⁴₂He

The superscript 4 to the left of the chemical symbol is the mass number: 2 protons + 2 neutrons = 4

The subscript 2 to the left of the chemical symbol is the atomic number: 2 protons = 2.

Hence, the statement "a. Alpha particles have a mass number of 4" is true.

As for the other statements, you have:

b. Alpha particles have a nulear charge of +1: false

Since, these particles are the nucleous of the helium atom, the nuclear charge equals the number of protons of this atom: +2. Hence, the statement is false.

c. Alpha particle formation is accompanied by the conversion of a proton into a neutron and d. Alpha particle formation is accompanied by the conversion of a neutron into a proton. (both false)

The conversion of a protons into a neutrons and the conversion of a neutron into a proton are product of other kind of radiactive desintegrations.

The conversion of a proton into a neutron involves the emission of a positron ( particle with same mass as the electron but positive charge) from the nucleus, which is represented as ⁰₊₁β.

The conversion of a neutron into a proton involves the emssion of an electron from the nucleus, which is the emission of a beta particle represented as ⁰₋₁β.

Therefore, these last two statements are also false.

4 0

2 years ago

You have just isolated a new radioactive element. If you can determine its half-life, you will win the Nobel Prize in physics. Y

lbvjy [14]

Answer: 2.58 days

Explanation:

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant = ?

t = age of sample = 6 days

a = initial amount of the reactant = 1 g

a - x = amount left after decay process = 0.2 g

a) to find the rate constant

$6=\frac{2.303}{k}\log\frac{1.0}{0.2}$

$k=\frac{2.303}{6}\log\frac{1.0}{0.2}$

$k=0.268days^{-1}$

b) for completion of half life:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

$t_{\frac{1}{2}}=\frac{0.693}{k}$

$t_{\frac{1}{2}}=\frac{0.693}{0.268}=2.58days$

The half life is 2.58 days

3 0

3 years ago

What is the volume of 2 mol of chlorine gas at STP? 2.0 L 11.2 L 22.4 L 44.8 L

nirvana33 [79]

Answer:

44.8 L

Explanation:

Using the ideal gas law equation:

PV = nRT

Where;

P = pressure (atm)

V = volume (L)

n = number of moles (mol)

R = gas law constant (0.0821 Latm/molK)

T = temperature (K)

At Standard temperature and pressure (STP);

P = 1 atm

T = 273K

Hence, when n = 2moles, the volume of the gas is:

Using PV = nRT

1 × V = 2 × 0.0821 × 273

V = 44.83

V = 44.8 L

7 0

2 years ago

The blank solution used to calibrate the spectrophotometer is 10.0 mL of 0.2 M Fe(NO3)3 diluted to 25.0 mL with 0.1 M HNO3. Why

Sliva [168]

FeNCS+ product...............thats how you do it i believe

4 0

2 years ago

Iron is extracted from iron oxide in the Blast Furnace: Fe 2 O 3 + 3 CO → 2 Fe + 3 CO 2

arsen [322]

a. mass of iron = 69.92 g

b. percent yield = 93%

<h3>Further eplanation </h3>

Percent yield is the compare of the amount of product obtained from a reaction with the amount you calculated

General formula:

Percent yield = (Actual yield / theoretical yield )x 100%

An actual yield is the amount of product actually produced by the reaction. A theoretical yield is the amount of product that you calculate from the reaction equation according to the product and reactant coefficients

Reaction

Fe₂O₃+3CO⇒2Fe+3CO₂

MW Fe₂O₃ : 159.69 g/mol

mol Fe₂O₃

$\tt \dfrac{100}{159,69}=0.626$