Answer:
Option (A)
Explanation:
Radioactivity is defined as a process in which an unstable atomic nucleus decays continuously and after a specific period of time changes into a much more stable element. During this time of decay, the nucleus emits charged particles (energy) which are known as the α, β and γ particles. These are often emitted in the form of electromagnetic energy and are very dangerous to health.
The radioactive elements decay at a certain rate which is commonly known as the half-life. Half-life is basically defined as the time required by a radioactive substance to decay half of its initial composition.
Thus, the correct answer is option (A).
In a chemical change, the molecules in the reactants interact to form new substances. In a physical change, like a state change or dissolving, no new substance is formed.
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Molecules move to the location of a chemical change due to the process of diffusion. In this physical phenomenon, molecules move from an area of high concentration to an area of lower concentration. This diffusion leads to interaction between reactant molecules causing the chemical change.
The movement of molecules to the location of a chemical change is a fundamental concept in Chemistry. In a chemical reaction, molecules move due to a physical phenomenon known as diffusion. Diffusion is the process by which molecules of a substance move from an area of high concentration to an area of lower concentration. For example, if you open a perfume bottle at one end of a room, eventually the perfume molecules will spread throughout the room. These perfume molecules move to areas of lower concentration via diffusion. In the context of a chemical reaction, the reactant molecules diffuse to interact with each other, leading to the chemical change or reaction.
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Answer:
Explanation:
The atomic number of zinc is 30, which means that the neutral atom has equal numbers of protons and electrons, so a neutral atom of zinc would have 30 electrons.
The electron configuration of a neutral zinc atom is 1s
2
2s
2
2p
6
3s
2
3p
6
3d
10
4s
2
.
The Zn
2+
ion has lost two electrons, which leaves it with 30 protons and 28 electrons.
The electron configuration of Zn
2+
is 1s
2
2s
2
2p
6
3s
2
3p
6
3d
10
.
b. canola oil
c. peanut oil
d. sunflower oil
Answer:
Canola Oil
Explanation:
The data given is as;
Oil Melting Point / Freezing Point
Canola Oil 10 °C
Corn Oil -11 °C
Sunflower Oil -17 °C
Peanut Oil -2 °C
When the mixture of these oils is cooled to 5 °C only the Canola oil will solidify because it has a melting point of 10 °C and exists in solid state below 10 °C (Freezing Point). Therefore, it can easily be separated from remaining mixture which is present in liquid state.
Answer:
The correct answer is D.
Explanation:
A chemical compound is any substance composed of identical molecules formed by atoms of two or more chemical elements. All matter in the universe is composed of atoms of more than 100 different chemical elements. These elements are found in pure form and combined form in chemical compounds.
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The initial volume of the gas is 117L.
Volume is the amount of space the matter occupies.
PV/T = k
where P = pressure, V = volume, T = absolute temperature in K and k= constant.
P1V1 / T1 = P2V2 / T2
Where P1 and P2 = initial and final pressure in atm
T1 and T2 = Initial and final temperature in K
V1 and V2 = initial and final volume in L
Using combined gas law:
P1V1/T1 = P2V2/T2
Given:
P1 = 0.5 atm
T1 = 325K
P2 = 1.2 atm
V2 = 48L
T2 = 320K
Assuming that the number of moles are constant for both conditions:
(P1 x V1)/T1 = (P2 x V2)/T2
Substituting the given values,
(0.5 x V1)/325 = (1.2 x 48)/320K
Solving for V1
V1 = (1.2atm x 48L x 325K)/ (320Kx 0.5 atm)
V1 = 117L
Hence, the initial volume of the gas is 117L.
To learn more about combined gas law here
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