Answer:

Explanation:
Calcium is the element of the group 2 and period 4 which means that the valence electronic configuration is
.
Chlorine is the element of the group 17 and period 3 which means that the valence electronic configuration is
.
Thus, calcium losses 2 electrons to 2 atoms of chlorine and these 2 atoms of chlorine accepts each electron to form ionic bond. This is done in order that the octet of the atoms are complete and they become stable.
Ca Cl
2 1
Cross multiplying the valency, We get, 
Thus, the formula of calcium chloride is
.
Answer:
A. a new substance is being produced.
Explanation:
The bubbles most likely indicates that a new substance is being produced by this reaction. In essence, we describe this sort of change as chemical change.
In a chemical change, new substances are usually produced. They are accompanied by the evolution or absorption of energy.
The reaction of Zinc with a strong acid to produce bubbles on the surface of the metal indicates a chemical change and the formation of a new kind of substance.
Take for example, let zinc reacts with hydrocholoric acid, HCl;
Zn + 2HCl → ZnCl₂ + H₂
Since Zn is higher than Hydrogen in the activity series, it will displace it from HCl and liberate hydrogen gas as a product. This will cause the bubbles observed in the reaction.
This is a chemical change and new products have been formed.
B and D are wrong because they are both physical changes.
C is wrong because no information about such is provided by the problem statement.
So, when a piece of zinc metal combines with a strong acid, a new kind of substance is produced.
Answer:
-41. 47
Explanation:
m = q / Cp x T
m = Mass
q = Energy (or joules)
Cp = Heat Capacity
T = Change in Temperature
Water's heat capacity is always 4.18.
This is the formula you'll need for change in temperature:
Final - Initial
So, 33 - 78 = -45
m = 7800 / 4.18 x -45
= -41.47
Packing
Explanation:
Ionic crystals are brittle due to the tight packing of their crystals. This provides little to no mobility between one another.
- Brittleness implies having little to no elasticity.
- Ionic crystals are held together by strong crystal lattice forces
- These forces prevents crystals from freely rotating and moving space.
- It holds them rigidly and fixed in place.
- Ionic crystals are hard and held electrostatic forces.
learn more:
Ionic compounds brainly.com/question/6071838
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Answer
Africa
Explanation:
Burning fossil fuels and deforestation is disturbingly heightened in Africa with almost no viable measure taking to control it's effect. No effective programs are presently in place to control excessive tree falling used for herbs, firewood, charcoal business and a whole lot. Below standard carbon rating PMS are in high circulation with fumes, carbon monoxide is full abundance in the atmosphere. Presently, all these unchecked activities have resulted into unexplainable excessive increase in temperatures, breeding neck twisting diseases, severe skin infections, dehydration and increase diabetes. Drought has eaten up landlocked cities in Nigeria and Central Africa. Infact farmers have lost count of the usual natural cycle of rainfall and the beginning of each farming season due to this essential evil of climate change