Answer:
The correct option is:
A) by direct or indirect contact between objects at different temperatures
Explanation:
Heat can be transferred in three different methods:
Conduction, Convection and Radiation
Conduction is heat transfer through direct contact between substances at different temperatures.
Convection is the heat transfer which takes place through air currents.
Radiation is the heat transfer that does not require contact between two objects.
Hence, heat transfer can take place through direct or indirect contact between objects at different temperatures.
Answer:
Explanation:
The covalent bond is the chemical bond between atoms where electrons are shared, forming a molecule. Covalent bonds are established between non-metallic elements, such as hydrogen H, oxygen O and chlorine Cl. These elements have many electrons in their outermost level (valence electrons) and have a tendency to gain electrons to acquire the stability of the electronic structure of noble gas.
The covalent bond between two atoms can be polar or nonpolar. If the atoms are equal, the bond will be nonpolar (since no atom attracts electrons more strongly). But, if the atoms are different, the bond will be polarized towards the most electronegative atom, because it will be the atom that attracts the electron pair with more force. Then it will be polar.
It can occur in a molecule that the bonds are polar and the molecule is nonpolar. This occurs because of the geometry of the molecule, which causes them to cancel the different equal polar bonds of the molecule.
In carbon tetrachloride the bonds are polar, but the tetrahedral geometry of the molecule causes all four dipoles to cancel out and the molecule to be apolar.
I think that its a ketone.
We have to look for safe and non - hazardous characterstics when trying to find new propellants.
<h3>What are propellants ?</h3>
Propellants are any gas, liquid, or solid the expansion of which can be used to impart motion to another substance or object.
The Desirable properties for propellant combinations are ;
- low molecular mass and high temperature of reaction products (for high exhaust velocity),
- high density (to minimize tank weight),
- low hazard factor (e.g., corrosivity and toxicity),
- low environmental impact,
- low cost.
Learn more about propellants here ;
brainly.com/question/1395855
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So the whole point is that you need a abstract.
