Potential energy stored in a spring => kinetic energy of a toy
I think the best answer that will describe chemical change is the first option. During a chemical change, b<span>oth the identity and the properties of a substance change because new substances are being formed by a chemical reaction. An example is rusting of steel</span>
Answer:
Percentage of copper = 88%
Explanation:
Given data:
Mass of copper = 51.2 g
Mass of tin = 6.84 g
Percentage of copper = ?
Solution:
Formula:
Percentage of copper = mass of copper / total mass × 100
Now we will determine the total mass:
Total mass = mass of copper + mass of tin
Total mass = 51.2 g + 6.84 g
Total mass = 58.04 g
Now we will calculate the percentage of copper.
Percentage of copper = 51.2 g / 58.04 g × 100
Percentage of copper = 0.88 × 100
Percentage of copper = 88%
Answer:
Net ionic equation:
Zn²⁺(aq) + 2OH⁻(aq) → Zn(OH)₂(s)
Explanation:
Chemical equation:
ZnCl₂ + KOH → KCl + Zn(OH)₂
Balanced chemical equation:
ZnCl₂ + 2KOH → 2KCl +Zn(OH)₂
Ionic equation;
Zn²⁺(aq) + 2Cl⁻(aq) + 2K⁺(aq) + 2OH⁻(aq) → 2K⁺(aq) + 2Cl⁻(aq) +Zn(OH)₂(s)
Net ionic equation:
Zn²⁺(aq) + 2OH⁻(aq) → Zn(OH)₂(s)
The K⁺ and Cl⁻ are spectator ions that's why these are not written in net ionic equation. The Zn(OH)₂ can not be splitted into ions because it is present in solid form.
Spectator ions:
These ions are same in both side of chemical reaction. These ions are cancel out. Their presence can not effect the equilibrium of reaction that's why these ions are omitted in net ionic equation.
Answer:
Pollution, non native species being introduced, and other human activities
Explanation:
Human activities affect marine ecosystems as a result of pollution, overfishing, the introduction of invasive species,and acidification, which all impact on the marine food web and may lead to largely unknown consequences for the biodiversity and survival of marine life forms.
