Answer:
0.375 M
Explanation:
NaOH(aq) + HBr(aq) ------------> NaBr(aq) + H2O(l)
Concetration of acid CA= 0.250M
Concentration of base CB= ????
Volume of acid VA= 30.0mL
Volume of base VB= 20.0mL
Number of moles of acid nA= 1
Number of moles of base nB= 1
CA VA/CB VB= nA/nB
CB= CAVAnB/VB nA
= 0.25× 30×1/20×1= 0.375 M
Answer:
1) 0.0625 g.
2) 0.0125 g.
Explanation:
<em>1) A solution of NaOH has a concentration of 25.00% by mass. What mass of NaOH is present in 0.250 g of this solution?</em>
mass% of NaOH = [(mass of NaOH)/(mass of solution)] x 100.
mass% of NaOH = 25.0%, mass of NaOH = ??? g, mass of solution = 0.250 g.
∴ mass of NaOH = (mass% of NaOH)(mass of solution)/100 = (25.0%)(0.250 g)/100 = 0.0625 g.
<em>2) What mass of NaOH must be added to the solution to increase the concentration to 30.00% by mass?</em>
We can use the relation:
mass% of NaOH = [(mass of NaOH)/(mass of solution)] x 100.
mass% of NaOH = 30.0%, mass of NaOH = ??? g, mass of solution = 0.250 g.
∴ mass of NaOH = (mass% of NaOH)(mass of solution)/100 = (30.0%)(0.250 g)/100 = 0.075 g.
∴ The mass of NaOH should be added = 0.075 - 0.0625 = 0.0125 g.
Answer: Electrovalent bonds are produced when electrons are transferred from atoms of one element to atoms of another element, producing positive and negative ions. The bond which is formed by the transfer of electrons between the atoms is called electrovalent bond or ionic bond. Electrovalent bonds are only formed between metals and non-metals. Electrovalent bonds are not formed between two non-metals.
In simple words electrovalent bond involves the transference of a certain number of electrons to another dissimilar atom which has a tendency to gain electrons so that both acquire stable inert gas configurations. The electrostatic attraction always tends to decrease the potential energy. Hence, the potential energy of the system is much less than it was before the formation of an ionic bond.
Explanation: An Ionic bond is the bond formed by the complete transfer of valence electron to attain stability.
This type of bonding leads to the formation of two oppositely charged ions – positive ion known as cations and negative ions are known as anions.
The presence of two oppositely charged ions results in a strong attractive force between them. This force is an ionic or electrovalent bond.
Ionic bonds form between atoms with large differences in electronegativity, whereas covalent bonds formed between atoms with smaller differences in electronegativity.
The compound formed by the electrostatic attraction of positive and negative ions is called an ionic compound.
Answer:
Explanation:
B because it has a lower activation energy
Answer:
True
Explanation:
To begin with,
Hydrogen bonds are attractions that contain a force caused by the difference in charge. This is due to the positive hydrogen ions as well as slightly negative ions. Therefore, hydrogen bonds make water molecules 'sticky.' To add, the attractions between hydrogen bonds are weaker than ionic and covalent bonds but strong enough to cause them to 'stick together'
Hope this helps.
