A chemical change
Explanation:
In this reaction, a chemical change has occurred, here are some indicators of chemical changes from the reaction;
Chemical changes are changes in which new products are formed.
- Formation of bubbles and precipitates: these are new substances that indicates a chemical change. The bubbles and insoluble precipitate are good indicators of chemical change.
- A temperature change that is large; This is also typifies chemical changes. When temperature rises in reaction, a chemical change has occurred.
- The bubbles and precipitates cannot be combined to give the reactants. The reaction is irreversible.
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Answer: C) Non-metals can share pairs of electrons and form covalent bonds
Explanation: The principal reason why it is non-metals that can form covalent bonds is because of their electronegativities. Electronegativity is the tendency of an atom to attract electrons towards itself.
The participating atoms in a covalent bond have to be able to hold the shared electron in place & it is this attraction towards the centre of each participating atom that holds the electrons in place. Metals aren't electronegative, they don't attract electrons towards each other, they'd rather even push the electrons away from themselves (electropositive) to be stable. The closest concept of metals to shared electrons is in metallic bonding, where metals push and donate their valence electrons to an electron cloud which is free to move around the bulk of the metallic structure. But this is nowhere near the type of bonding that exist in covalent bonds.
It's b. calcium
because the outer electron structure in all of that element is similar, they have the same chemical and physical properties.<span />
To determine the Ka of the acid, we can use the equation for the pH of weak acids which is expressed as:
pH = -0.5 log Ka
2.67 = -0.5 log Ka
Ka = 4.571x10^-6
Weak acids are acids that do not dissociate completely in solution. The solution would contain the cations, anions and the acid itself as a compound. Hope this helps.