Answer:The Geocentric and the Heliocentric models are descriptions of the universe known at the time when these models were developed. The main difference between the two models is the perceived center of the known universe. According to the geocentric model, Earth is the center of the known universe
Explanation:I answerd the question before in Earth Science
Answer:
Mass = 2.77 g
Explanation:
Given data:
Mass of HCl = 2 g
Mass of CaCl₂ produced = ?
Solution:
Chemical equation:
2HCl + Ca → CaCl₂ + H₂
Number of moles of HCl:
Number of moles = mass / molar mass
Number of moles = 2 g/ 36.5 g/mol
Number of moles = 0.05 mol
now we will compare the moles of HCl with CaCl₂.
HCl : CaCl₂
2 : 1
0.05 : 1/2×0.05 = 0.025 mol
Mass of CaCl₂:
Mass = number of moles × molar mass
Mass = 0.025 mol × 110.98 g/mol
Mass = 2.77 g
In a beta emission, the mass number of the daughter nucleus remains unchanged while the atomic number of the daughter nucleus increases by one unit. The following are isotopes produced when the following undergo beta emission;
1) potassium-42 ------> Ca - 42
2) iodine-131 ------------> Xe - 131
3) iron-52 ---------------> Co - 52
4) sodium-24 -----------> Mg -24
The daughter nucleus formed after beta emission is found one place after its parent in the periodic table.
Regarding the stability of the daughter nuclei, a nucleus is unstable if the neutron-proton ratio is less than 1 or greater than 1.5.
Hence, the following daughter nuclei are stable; Ca - 42, Xe - 131, Mg -24.
Learn more: brainly.com/question/1371390
Answer:
Bubbling/Foaming
Heat is produced
Explanation:
A chemical reaction has occurred if
1. There is a change in colour
2. Formation of a precipitate
3. Formation of a gas
4. Change in temperature
5. Change of smell
In the reaction of hydrogen peroxide and potassium iodide, the solution quickly rises which shows the formation of gas. This means it is a chemical reaction.
The beaker/test tube/whatever you used should also become warm because it is an exothermic reaction. This means its a chemical reaction
