Answer: it has ice in it and that makes the things you use with the cold pack colder
The mass of N-15 is 15 amu.
Chemical elements are represented using their symbols, their mass number and their proton numbers. The mass number of this isotope of nitrogen is shown next to the symbol. Regardless of the mass of the isotopes, their proton number is the same, which is 7.
Answer:
a) formula for citric acid is - C6 H8 o7
b) lime water turns opaque after adding co2 due to the formation of calcium carbonate.
c) reaction 3 is displacement reaction where a high reactive metal displace a less reactive from its salt solution.
d) reaction 1) is combination reaction where two reactant combines to give a single product whereas reaction 2) is decomposition reaction where a single reactant splits into more that 1 products.
Answer:
1) Ca: [Ar]4s²
2) Pm: [Xe]6s²4f⁵
Explanation:
1) Ca:
Its atomic number is 20. So it has 20 protons and 20 electrons.
Since it is in the row (period) 4 the noble gas before it is Ar, and the electron configuration is that of Argon whose atomic number is 18.
So, you have two more electrons (20 - 18 = 2) to distribute.
Those two electrons go the the orbital 4s.
Finally, the electron configuration is [Ar] 4s².
2) Pm
The atomic number of Pm is 61, so it has 61 protons and 61 electrons.
Pm is in the row (period) 6. So, the noble gas before Pm is Xe.
The atomic number of Xe is 54.
Therefore, you have to distribute 61 - 54 = 7 electrons on the orbitals 6s and 4f.
The resultant distribution for Pm is: [Xe]6s² 4f⁵.
Answer: The process by which a particular substance or different substances are transformed to another is called as Chemical Reaction.One reason, in the case of reversible reactions could be that the reaction reached equilibrium before the reaction was complete.Chemical reactions occur when chemical bonds between atoms are formed or broken. The substances that go into a chemical reaction are called the reactants, and the substances produced at the end of the reaction are known as the products.The concentration of reactants decreases as the reaction proceeds and at last their concentration comes to an end. Hence, the reaction stops too. If two reactants are being reacted, then the reactant which is in limited amount will consume first and will result in the termination of reaction.The usual reason is that one (or more) of the reactants gets used up.
Hope that was helpful.Thank you!!!
