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4 years ago

What is an isotope ? how is the mass calculated ?

Chemistry

1 answer:

leonid [27]4 years ago

8 0

Answer:

Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number. All isotopes of a given element have the same number of protons but different numbers of neutrons in each atom

Explanation:

For any given isotope, the sum of the numbers of protons and neutrons in the nucleus is called the mass number. This is because each proton and each neutron weigh one atomic mass unit (amu). By adding together the number of protons and neutrons and multiplying by 1 amu, you can calculate the mass of the atom

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I would say it’s ‘laws are based on complex theories’.

A scientific law predicts the outcome, while a theory presents a possible explanation to why this outcome is. A law is based of a theory that supports the most data.

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3 years ago

A 30 mL solution contains 5.2 g NaNO2. Calculate the molarity of the solution

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3 years ago

If an ideal gas has a pressure of 4.03 atm,

kkurt [141]

Answer:

PV=nRT where P=pressure in atm, V=volume is liters, n=numbber of moles, R=gas constant, 0.08206 L-atm/mole KL, and T=temperature in K (273 + C). So (5.67atm)(99.39L)=n(0.08206 L-atm/mol.K)(328.94K), solve for n, the number of moles, n=20.9 moles.

Explanation:

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3 years ago

What cells form enamel?

solniwko [45]

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Explanation:

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4 years ago

If 10.0 mL of a .600 M of HNO3 reacts with 31.0 mL of .700M Ba(OH)2 solution, what is the molarity of Ba(OH)2 after the reaction

Tasya [4]

Answer:

0.456M

Explanation:

1. Balanced molecular equation

$2HNO_3+Ba(OH)_2\rightarrow Ba(NO_3)_2+2H_2O$

2. Mole ratio

$\dfrac{2molHNO_3}{1molBa(OH)_2}$

3. Moles of HNO₃

Number of moles = Molarity × Volume in liters
n = 0.600M × 0.0100 liter = 0.00600 mol HNO₃

4. Moles Ba(OH)₂

n = 0.700M × 0.0310 liter = 0.0217 mol

5. Limiting reactant

Actual ratio:

$\dfrac{0.0600molHNO_3}{0.0217molBa(OH)_2}\approx0.28$

Since the ratio of the moles of HNO₃ available to the moles of Ba(OH)₂ available is less than the theoretical mole ratio, HNO₃ is the limiting reactant.

Thus, 0.006 moles of HNO₃ will react completely with 0.003 moles of Ba(OH)₂ and 0.0217 - 0.003 = 0.0187 moles will be left over.

6. Final molarity of Ba(OH)₂

Molarity = number of moles / volume in liters
Molarity = 0.0187 mol / (0.0100 + 0.0031) liter = 0.456M

5 0

3 years ago