Answer: A) grinding coffee beans
Explanation:
A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions.
A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions.
1. Grinding coffee : Only change in size takes place, thus a physical change
2. Baking a cake: the chemical reaction occurs by combination of flour with oxygen , thus a chemical change.
3.:converting water to hydrogen and oxygen: The decomposition iof water takes place, thus is a chemical change
4.Burning of coal: the chemical reaction occurs by combination of carbon with oxygen , thus a chemical change.
Answer:
Endangered. The meaning of endangered is when a species declines in number- this might be because they are being eaten by another animal which has a higher popupayion, or perhaps because they are being hunted by humans for their meat or fur. Neither reason might be that their food or habitat has been destroyed b humans to create land for farming or housing. one example of name endangered species is Polar Bears: they like in the Antarctic where there is no land, simply ice. Due to humans causing climate change, the world is warming up and the ice is melting. This means polar bears are dying out because it would be too tiring to swim to find ice. For the same reason, other animals are dying in the Antarctic meaning that Poplar Bears have less to eat (being at the top of the food chain -no animal eats polar bears).
Boiling point<span> is the </span>temperature<span> at which the vapor pressure of the liquid equals the surrounding pressure.
Above boiling point point, liquid get converted into vapour.
Now, boiling point of water is 100 oC at room pressure. Room pressure is equal to 760 torr. Thus, at 100 oC, vapour pressure of water becomes equal to 760 torr.
Now, if external pressure is increased to 880 torr, more heat is to be supplied so that vapour pressure of water equals 880 torr.
So, at 880 torr, boiling point of water will be more than 100 oC. In present case, most like the boiling point of water is equal to 105 oC.
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Answer:- Formula of the hydrate is 
and it's name is Iron(III)sulfate pentahydrate.
Solution:- As per the given information, there is 18.4% water in the hydrate. If we assume the mass of the hydrate as 100 grams then there would be 18.4 grams of water and 81.6 grams of Iron(III)sulfate present in the hydrate.
Molar mass for Iron(III)sulfate is 399.88 gram per mol and the molar mass for water is 18.02 gram per mol.
We will calculate the moles of Iron(III)sulfate and water present in the compound on dividing their grams by their molar masses as:
= 
= 
Now, the next step is to calculate the mol ratio and for this we divide the moles of each by the least one of them means whose moles are less. Here, the moles of Iron(III)sulfate are less than moles of water. So, we divide the moles of each by 0.204.
= 1
= 5
There is 1:5 mol ratio between Iron(III)sulfate and water. So, the formula of the hydrate is and the name of the hydrate is Iron(III)sulfate pentahydrate.
