Answer:
correct option: A. tetrahedral
Explanation:
when we talk about hydrogen bonding in water due to oxygen then need to check the number of lone pair available for hydrogen bonding because hydrogen bond form between lone pair of oxygen and hydrogen of other water molecule so there are two lone pair which forms hydrogen bond and there are also two other covalent bond with hydrogen of same molecule so total number is 4 it means they will form a tetrahedral geometry
<span>1. The correct option is A, THE OXYGEN ATOM HAS A NEGATIVE CHARGE. A water molecule is made up of two atoms of hydrogen and one atom of oxygen. The molecules of water are arranged in such a way that, the negative hydrogen atom is attracted to the positive hydrogen atom and the overall structure is bent. Because oxygen is more electronegative than hydrogen, oxygen atom draws the shared electrons toward itself , this gives the oxygen end of the molecule a partial negative charge and the hydrogen end, a partial positive charge.
2. The correct option is: WITHOUT THE PROPER BALANCE OF WATER, CHEMICAL REACTIONS WILL NOT TAKE PLACE. Metabolic chemical reactions take place in living cells all the time because water, which is a necessary condition for the reaction is in place. Th fluids find in the cells are mostly water; water creates suitable conditions for biochemical reactions to take place. Without water, the cells will not be able to carry out any chemical reaction.
3. The correct option is A. Hydrogen bond allows oxygen and water molecules to be bonded together. Hydrogen bonds are weak interactions that formed between the hydrogen with a patial positive end and oxygen with a patial negative end. The hydrogen bond in water is responsible for the unique properties associated with water.</span><span />
Answer:
A chemical change
Explanation:
The marshmallow turning brown and bubbling implies that a chemical change has taken place.
For chemical changes to occur, we observe any of the following:
- a new kind of matter is formed.
- it is always accompanied by energy changes
- the process is not easily reversible
- it involves a change in mass
- requires considerable amount of energy.
ii. Two signs that shows a chemical change has taken place is that:
- bubbles are being formed as it is roasted and it implies that new substances have been formed.
- also, significant amount of heat energy is supplied for the roasting.
False
Although we use many of their ideas to describe atoms today, such as the existence of a tiny, dense nucleus in an atom (proposed by Rutherford), or the notion that all atoms of an element are identical (proposed by Dalton), some of their ideas have been rejected by the modern theory of the atom.
For example, Thompson came up with the plum pudding model to describe an atom, which resembled a sphere of positive charge with electrons embedded in it. We know now, however, that atoms are mostly empty space with a tiny, dense nucleus.
Another example is Dalton's atomic theory, which stated that atoms are indivisible particles. However, this was disproved by the discovery of subatomic particles.
38.46g
Explanation:
Given parameters:
Mass of CaF₂ = 75.0g
Unknown:
Mass of calcium that can be recovered = ?
Solution:
This is a mass percentage problem and we need to solve it accordingly.
To solve this problem;
Find the molar mass of CaF₂
Find the ratio between the molar mass of Ca and that of CaF₂
Multiply by the given mass
Molar mass of CaF₂ = 40 + (2 x 19) = 78g/mol
Mass of calcium = 
x 75 = 38.46g
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Mass percentage brainly.com/question/8170905
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