Answer:
3.75 g.
Explanation:
<em>mass percent is the ratio of the mass of the solute to the mass of the solution multiplied by 100.</em>
<em />
<em>mass % = (mass of solute/mass of solution) x 100.</em>
<em></em>
mass of calcium nitrite = ??? g,
mass of the solution = 25.0 g.
∴ mass % = (mass of solute/mass of solution) x 100
<em></em>
<em>∴ mass of solute (calcium nitrite) = (mass %)(mass of solution)/100</em> = (15.0 %)(25.0 g)/100 = <em>3.75 g.</em>
From the reaction between Cu and HNO₃, the formed gas is NO₂ instead of NO₃. Hence the correct balanced equation would be,
Cu(s) + 4HNO₃(aq) → Cu(NO₃)₂(aq) + 2NO₂(g) + 2H₂O<span>(l)
Here, Cu goes to </span>Cu(NO₃)₂ by changing its oxidation number from 0 to +2 while NO₃⁻ goes to NO₂ by reducing its oxidation state from +5 to +4 . Hence Cu is oxidized by HNO₃ in the reaction.
There are some exceptions to the rule organisms such as a protist called a euglena can be both heterotrophic and autotrophic. This is a true statement.
Explanation:
- Euglena is a large genus of unicellular protists: they have both plant and animal characteristics
- Photoautotrophs include protists that have chloroplasts, such as Spirogyra. Heterotrophs get their energy by consuming other organisms. Other protists can get their energy both from photosynthesis and from external energy sources
- All live in water and move by means of a flag ellum. This is an animal characteristic. Most have chloroplasts, which are characteristic of algae and plants
- Euglena is photosynthetic in the presence of sunlight i.e autotrophic, when deprived of sunlight they behave like heterotrophs by predating on other smaller organisms.
- Most species of Euglena have photosynthesizing chloroplasts within the body of the cell, which enable them to feed by autotrophy, like plants. They can also take nourishment heterotrophically, like animals.
Answer:
Conduction is the transfer of thermal energy from one molecule to another within an object. Conduction also happens between two objects in direct contact if they have different temperatures. The hotter molecule vibrates because of the added heat. This vibration and movement transfer the energy to the surrounding molecules. The transfer of energy continues until all the molecules have the same temperature.
Conduction takes place in solids, liquids, and gases. However, it happens fastest in solids because the molecules in solids are closely packed.
