Answer:
an atom is the smallest unit of matter or a substance.
Explanation:
the structure of the
atom consists of electrons, protons, neutrons) which makes up the nucleus is more than a hundred thousand times smaller than it's atom but makes up 99.9% of the mass of the atom.
the protons are the positively charged particles. The neutrons are the negatively charged particles. The electrons are the negatively charged particles.
the first energy level consists of two electrons. the second energy level consists of eight electrons. the 3 energy level consists of eighteen electrons. the 4 energy level consists of thirty two electrons.
Answer : Colloid
Explanation : Any colloid which consist of a solid evenly dispersed in a gas phase can be called as smoke. So, if smoke has to be given a matter of substance then it is can be categorized as a Colloid present in gaseous phase. Smoke is a solid which contains minute particles of dust which is homogeneously dispersed in the air.
Answer:
Explanation:Reaction NaHCO3 + HCl ⇒ NaCl + H2O + CO2
Molar mass M = (22.99+1.008+ 12.01+3·16 ) g/mol. Calculate
Amount of substance n =m/M, n(NaCl) is equal.
M(NaCl) = 58.44 g/mol and mass m= n·M
Answer:
As you haven't explained what measurements you took before solving this problem, I will explain the general procedure to evaluate the efficiency of a kettle. I hope it helps you. I´ll send an attachement file with the full answer, since I couldn't write it here.
I assume that the material that is going to be heated in the kettle is water.
1- You have to boil water in it and take the time it takes to its boiling point (in seconds).
2- You have to evaluate the amount of energy the water absorbed Q with the efficiency formula which I explain in the attachement file.
3- Divide Q by the time it took to bring the water to boiling so you can have the power it consumed.
4- You divide the last value you obtained by the Kettles's power rating.
5- Multiply the last value by 100 to obtain a percentage value of efficiency.
Explanation:
Efficiency is the ration of a machine's useful work, in this case how much energy the water absorbed to get to its boiling point divided by the time it took to get to this point, and the total energy expended, in this case the kettles's power rating.