Answer:
3,4
Explanation:
Hydrogen has no other electron hence there is no screening of the valence electron by inner electrons. It is the lightest known element with a relative molecular mass of 2. Screening effect refers to the fact that inner or core electrons prevent the outermost electron from feeling the attractive force of the nucleus.
The conversions that will be used are:
1 mole of copper / 63.5 grams of copper
6.02 x 10²³ atoms of copper / 1 mole of copper
Multiplying the given mass by these conversions,
660 g * (1 mol Cu / 63.5 g Cu) * (6.02 x 10²³ Cu atoms / 1 mole Cu)
The sample contains 6.25 x 10²⁴ atoms of copper
<u>0.4 mol of </u>
molecules has larger mass than 0.4 mol of O atoms
<h3>What are molecules?</h3>
The smallest component of a substance that possesses both its chemical and physical characteristics. One or more atoms make up molecules.
They may have the same atoms (for example, an oxygen molecule has two oxygen atoms) or different atoms if they have more than one (a water molecule has two hydrogen atoms and one oxygen atom). Biological molecules like DNA and proteins can include thousands of atoms.
the lowest recognised unit into which a pure material can be divided while retaining its chemical makeup and attributes is made up of two or more atoms.
Learn more about Molecules
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Answer:
98.6 g/mol.
Explanation:
Equation of the reaction
HX + NaOH--> NaX + H2O
Number of moles = molar concentration × volume
= 0.095 × 0.03
= 0.00285 moles
By stoichiometry, 1 mole of HX reacted with 1 mole of NaOH. Therefore, number of moles of HX = 0.00285 moles.
Molar mass = mass ÷ number of moles
= 0.281 ÷ 0.00285
= 98.6 g/mol.
