1) Write the balanced chemical equation
2HCl + Na2 CO3 ----------> 2NaCl + H2CO3
2) Write the molar ratios:
2 mol HCl : 1 mol Na2CO3 : 2 mol NaCl : 1 mol H2CO3
3) Convert 0.15g of sodium carbonate to number of moles
3a) Calculate the molar mass of Na2CO3
Na: 2 * 23 g/mol = 46 g/mol
C: 12 g/mol =
O: 3 * 16 g/mol = 48 g/mol
molar mass = 46g/mol + 12g/mol + 48g/mol = 106 g/mol
3b.- Calculate the number of moles of Na2CO3
# moles = grams / molar mass = 0.15 g / 106 g/mol = 0.0014 mol Na2CO3
4) Calculate the number of moles of HCl from the molar proportion:
[0.0014 mol Na2CO3] * [2 mol HCl / 1 mol Na2CO3] = 0.0028 mol HCl
5) Calculate the volume of HCl from the definition of Molarity
Molarity, M = # moles / volume in liters
=> Volume in liters = # moles / M = 0.0028 mol / 0.1 M = 0.028 liters
0.028 liters * 1000 ml / liter = 28 ml.
Answer: 28 mililiters of 0.1 M HCl.
Answer:
Pretty sure its a mineral
Explanation:
Beeswax is a naturally occurring wax secreted mainly by honeybees A. mellifera, for constructing honey combs (Tulloch, 1970a). Unhydrolyzed beeswax consists of approximately 71% esters, 15% hydrocarbons, 8% free fatty acids, and 6% other components (Tulloch, 1970b).
Answer:
d) cut the large sized Cu solid into smaller sized pieces
Explanation:
The aim of the question is to select the right condition for that would increases the rate of the reaction.
a) use a large sized piece of the solid Cu
This option is wrong. Reducing the surface area decreases the reaction rate.
b) lower the initial temperature below 25 °C for the liquid reactant, HNO3
Hugher temperatures leads to faster reactions hence this option is wrong.
c) use a 0.5 M HNO3 instead of 2.0 M HNO3
Higher concentration leads to increased rate of reaction. Hence this option is wrong.
d) cut the large sized Cu solid into smaller sized pieces
This leads to an increased surface area of the reactants, which leads to an increased rate of the reaction. This is the correct option.
Each correspond to a principal energy level
Answer: option D. The attractive forces between the sodium and chloride ions are overcome by the attractive forces between the water and the sodium and chloride ions.
Explanation:
<em>Solid sodium chloride</em> (NaCl) is a ionic compound formed by ionic bonds between by the positive, metallic cations of sodium atom, Na⁺, and the negative, non-meatllic anions of chlorine atom, Cl⁻ (chloride).
Ionic bonds, then, are the electrostatic attracion between oppositely charged particles (cations and anions).
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<em>When solid sodium chloride dissolves in water</em>, the ions (cations and anions) are separated in the solvent (water) due to the superior attracitve forces between such ions and the polar water molecules.
<em>Water</em> (H₂O) is a molecule, formed by polar covalent bonds between two hydrogen atoms and one oxygen atom.
The polarity of water molecule is due to the fact that oxygen atoms are more electronegative than hydrogen atoms, which cause that the electron density is closer to oxygen nuclei than to hydrogen nuclei. This asymmetry in the electron density conferes a partial positive charge over each hydrogen atom and a partial negative charge over the oxygen atoms.
Thus, the positively charged hydrogen atoms attract and surround the negative chloride (Cl⁻) anions, while the negatively charged oxygen atoms attract and surround the positive sodium (Na⁺) cations. It is only because the attractive forces between the water and the sodium and chloride ions are stronger than the attractive forces between the sodiium and chloride ions that such ions may be kept separated in the solution. This process is called solvation and the ions are said to be solvated by the water molecules.
