ANSWER
there are 20 number of atoms in compound
Explanation:
In a formula unit of Mg(OH)2, there are one magnesium ion and two hydroxide ions; or one magnesium, two oxygen, and two hydrogen atoms.
Answer:
1. Litres
2. minutes
3. Kelvin (K)
4. Kilometer/hour
5. hours
6. Litre
7. metre
8. metre
9. Litres
10. milliliters
Explanation:
1. Coca-Cola is a liquid substance, hence, its volume must be measured in LITRES.
2. This question is related to time I.e. being early, hence, the unit of measurement is MINUTES.
3. The unit of temperature is Kelvin (K). Therefore, water boils at 373K
4. This question is related to speed, whose unit of measurement is kilometer/hour (km/hr).
5. A movie runs with time, which is measured in HOURS.
6. Mineral water is a liquid, which can only be bought per volume. Hence, the appropriate unit is LITRE.
7. Height is measured in metres (m). Therefore, one can say that " the height of your younger brother is 10metres"
8. The length of a substance is also measured in metres.
9. Volume is measured in LITRES
10. Cough syrup is a drug whose volume is quantified by millilitres i.e. a thousandth litre
Answer:
The unknown element is Carbon.
(a) X is Carbon, its oxide is of acidic nature
(b) C+ O2 → CO2
Explanation:
We are given an unknown element that reacts with oxygen.
X + O2 → XO2
It is given that the oxide XO2 turns blue litmus red which is shown by acids, so XO2 is an acidic oxide. Also X will be a Non metal because Non metallic oxide is Acidic in nature.
The Oxide XO2 is dissolving is water. The oxide upon reacting with water will give an Acid.
XO2 type of oxide is found in the 14th group of the periodic table generally
So we have options like C, Si and Ge as these only have the Acidic oxide.
But when it comes to reactivity with water Only Carbon satisfies the need so the unknown element X is C.
CO2 + H2O → H2CO3 which is an acid.
(a) Element X is Carbon (C), The nature of the compound formed is Acidic.
(b) The reaction given will be as follows
C+ O2 → CO2
Therefore the unknown element is Carbon.
A solar eclipse occurs when a portion of the Earth is engulfed in a shadow cast by the Moon which fully or partially blocks sunlight. This occurs when the Sun, Moon and Earth are aligned.
Answer:
Advantages: More land has been made available for development. More buildings and infrastructure can be built, and also for other reasons.
Disadvantages: Much greenery has been removed in order for the land needed. Land reclamation can be damaging to corals and marine life. Corals are usually moved to another place when land is to be reclaimed. The corals might not be able to survive in that certain habitat, and thus die out. In some countries, where the project is large-scale, they do not even bother to re-plant the corals elsewhere, instead just reclaim the land on their habitat, causing them to die out immediately. Marine life, such as fishes, might not have enough food after the underwater plantations are destroyed due to reclamation of land. This applies to the food chain. The waters might also be polluted from the soil used to reclaim land, causing the fishes to die and blocking out sunlight, depriving the underwater plants of growth. Marine habitats are also destroyed, as mentioned earlier; therefore, the marine creatures would be forced to move to another new habitat. Some might not be able to adapt, and thus die out. Some would just die without even finding a new habitat, as they cannot move long distances in water. Of course, the reasons and examples look tempting to us humans, but marine life is life too! We should try to protect is as much as possible, instead of just focusing on the advantages.
