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3 years ago

The atomic number of an element gives the number of and in the atom while the mass number gives the total number ofand

1 answer:

8 0

The atomic number of an element gives the proton and electron in the atom while the mass number gives the total number of protons and neutron

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What mass of chromium would be produced from the reaction of 57.0 g of potassium with 199 g of chromium(II) bromide according to

fredd [130]

Answer:

Mass of Chromium produced = 37.91 grams

Explanation:

2K + CrBr₂ → 2KBr + Cr

2mole 1 mole 1 mole

mass of Potassium = 57.0 grams

molar mass of Potassium = 39.1 g/mol

no of moles of Potassium = 57.0 / 39.1 = 1.458 moles

mass of CrBr₂= 199 grams

molar mass of CrBr₂ = 211.8 gram/mole

no of moles of CrBr₂ = 199 / 211.8 = 0.939 mole

From chemical equation

1 mole of CrBr₂ = 2 moles of K

∴ 0.939 moles of CrBr₂ = ?

⇒ 0.939 x 2/1 = 1.878 moles of K

1.878 moles of K is needed, but there is 1.458 moles of K. So, Potassium is completed first during the reaction . Hence, Potassium is limiting reagent. and CrBr₂ is excess reagent .

From chemical equation

2 moles of K = 1 mole of Cr

∴ 1.458 moles of K = ?

⇒ 1.458 x 1/ 2 = 0.729 moles of Cr

no of moles of Cr formed = 0.729 moles

molar mass of Cr = 52.0 g/mol

mass of one mole of Cr = 52.0 grams

mass of 0.729 moles of Cr = 52.0 x 0.729 = 37.908 grams

mass of Chromium produced = 37.91 grams

6 0

3 years ago

Question 19 of 25

Scrat [10]

Answer: the gas molecules interact with one another

Explanation:

7 0

2 years ago

What is the reason for the low solubility of LiF (0.27 g

Brut [27]

Answer:

The answer is C. The high solvation energy for LI+

Explanation:

LiF has lower solubility because of the high solvation energy of Li+ ion. This is due to the smaller size and very big charge compared to Cs+ ion which has a bigger size and solvent molecules easily surround it.

Solvation energy is simply the amount energy that is required to make a solute dissolve in a solvent.

3 0

3 years ago

Calculate the change in enthalpy for the following reaction, using the bond enthalpy data provided below. (Note: you may round t

aliina [53]

Answer:

-514 kJ/mol

Explanation:

The bond enthalpy which is also known as bond energy can be defined as the amount of energy needed to split one mole of the stated bond. The change in enthalpy of a given reaction can be estimated by subtracting the sum of the bond energies of the reactants from the sum of the bond energies of the products.

For the given chemical reaction, the change in enthalpy of the reaction is:

Δ $H_{rxn} =$ [2(409) + 4(388) + 3(496) - 4(630) - 4(463)] kJ/mol = 818 + 1552 + 1488 - 2520 - 1852 = -514 kJ/mol

3 0

4 years ago

A student states that the graduated cylinder contains 150 mL of water his statement is

Gre4nikov [31]

The correct answer is B. An observation

Explanation:

An observation is defined as a statement or conclusion you made after observing or measuring a phenomenon, this includes statements based on precise instruments. For example, if you conclude a plant grows 2 inches every month by measuring the plant during this time, this is classified as an observation. The conclusion of the student is also an observation because he concludes this after analyzing the volume of the water in the cylinder through the lines in the graduated cylinder, considering the water is just in the middle of 100 mL and 200 mL which indicates there are 150 mL of water.

8 0

3 years ago

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The atomic number of an element gives the number of __ and __in the atom while the mass number gives the total number of__and__

The atomic number of an element gives the number of and in the atom while the mass number gives the total number ofand