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3 years ago

Help please!!!!!!I have to have 20 caracters

Chemistry

2 answers:

KatRina [158]3 years ago

3 0

C. He discovered a new type of medicine that could treat infections

galben [10]3 years ago

3 0

C. He discovered a new type of medicine that could treat infections

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The nucleus of unstable _____ of an element will decay leading to emission of radiation.question 1 options:moleculescationsanion

Marta_Voda [28]

Isotopes of same element has different number of neutrons with different masses and having same number of protons and electrons.

Radioactive isotopes are those isotopes which are radioactive in nature. The unstable nucleus results in the radioactivity process and this process will go on until the stable isotope (element) forms.

Thus, the nucleus of unstable isotopes of an element will decay leading to emission of radiation.

6 0

3 years ago

The standard internal energy change for a reaction can be symbolized as Δ U ∘ rxn or Δ E ∘ rxn . For each reaction equation, cal

rosijanka [135]

Answer : The internal energy change is, -506.3 kJ/mol

Explanation :

Formula used :

$\Delta H=\Delta U+\Delta n_gRT$

or,

$\Delta U=\Delta H-\Delta n_gRT$

where,

$\Delta H$ = change in enthalpy = $-511.3kJ/mol=-511300.0J/mol$

$\Delta U$ = change in internal energy = ?

$\Delta n_g$ = change in moles

Change in moles = Number of moles of product side - Number of moles of reactant side

According to the reaction:

Change in moles = 0 - 2 = -2 mole

That means, value of $\Delta n_gRT$ = 0

R = gas constant = 8.314 J/mol.K

T = temperature = $25^oC=273+25=298K$

Now put all the given values in the above formula, we get

$\Delta U=\Delta H-\Delta n_gRT$

$\Delta U=(-511300.0J/mol)-[-2mol\times 8.314J/mol.K\times 298K$

$\Delta U=-511300.0J/mol+4955.144J/mol$

$\Delta U=-506344.856J/mol=-506.3kJ/mol$

Therefore, the internal energy change is -506.3 kJ/mol

6 0

3 years ago

Consider three gases: Ar, SF6, and Cl2. If 50.0 grams of these gases are placed in each of three identical containers, which con

adoni [48]

The ideal gas law:
$pV=nRT \Rightarrow p=\frac{nRT}{V}$
p - pressure, n - number of moles, R - the gas constant, T - temperature, V - volume

The volume and temperature of all three containers are the same, so the pressure depends on the number of moles. The greater the number of moles, the higher the pressure.
The mass of gases is 50 g.

$Ar \\
M \approx 39.948 \ \frac{g}{mol} \\
n=\frac{50 \ g}{39.948 \ \frac{g}{mol}} \approx 1.25 \ mol \\ \\
SF_6 \\
M \approx 146.06 \ \frac{g}{mol} \\
n=\frac{50 \ g}{146.06 \ \frac{g}{mol}} \approx 0.34 \ mol \\ \\
Cl_2 \\
M=70.9 \ \frac{g}{mol} \\
n=\frac{50 \ g}{70.9 \ \frac{g}{mol}} \approx 0.71 \ mol$

The greatest number of moles is in the container with Ar, so there is the highest pressure.

4 0

3 years ago

what is the products of the reaction between 2-methylbut-2-ene and HCL 1b. write the IUPAC names of the product of the reaction;

zzz [600]

Answer:

Explanation:

2 - chloro-2-methylbutane

8 0

3 years ago

Sodium phosphate and calcium chloride react to form sodium chloride and calcium phosphate. If you have 379.4 grams of calcium ch

barxatty [35]

Answer: 353.6 g.

Explanation:

1) Word equation (given)

Sodium phosphate + calcium choride → sodium chloride + calcium phosphate

2) Balanced chemical equation

2 Na₃PO₄ +3 CaCl₂ → 6 NaCl + Ca₃(PO4)₂

3) Mole ratio

2 moles Na₃PO₄ : 3 moles CaCl₂ : 6 moles NaCl : 1 mole Ca₃(PO4)₂

4) Formula to convert grams to moles

number of moles = mass in grams / molar mass

5) Number of moles of limiting reactant

a) mass in grams = 379.4 g CaCl₂

b) molar mass CaCl₂ = 110.98 g/mol

c) number of moles CaCl₂ = 379.4 g / 110.98 g/mol = 3.419 moles

6) Theoretical yield of Ca₃(PO4)₂

3 moles CaCl₂ / 1 mole Ca₃(PO4)₂ = 3.419 moles CaCl₂ / x ⇒

x = 3.419 × 1 / 3 = 1.140 moles Ca₃(PO4)₂

7) Convert 1.140 moles Ca₃(PO4)₂

a) molar mass Ca₃(PO4)₂ = 310.1767 g/mol

b) mass in grams = number of moles × molar mass = 1.140 moles × 310.1767 g/mol = 353.6 g ← answer.

7 0

3 years ago