Answer:
Gravity.
Explanation:
Black holes in the center of most galaxies hold the galaxy together by gravity. Everything is sucked towards the center and kept together.
Answer:
D. burning wood
Explanation: It seems like the only logical answer
All those compounds are ionic.
Then they dissociate into ions when they are in water.
I will write the dissociation equations. The charges of the ions is indicated inside parenthesis.
KI -> K (+) + I (-) => two ions
K2SO4 -> 2 k(+) + SO4 (2-) -> three ions
NaCl -> Na(+) + Cl(-) => two ions
KBr -> K(+) + Br(-)
As you se every molecule of the compound K2SO4 dissociates into three ions, while the other compounds dissociate into two ions. Given that the decrase in the freezong point of water is proportional to the number of particles dissolved, the K2SO4 will lower the freezing point the most.
Answer: option B. K2SO4
1. 2Al(s)+6HCl(aq)⇒2AlCl₃(aq)+3H₂(g)
2. 2AgNO₃ (aq) + Cu (s)⇒Cu(NO₃)₂ (aq) + 2Ag (s)
3. 2C₃H₈O(l) + 9O₂(g) ⇒ 6CO₂(g) + 8H₂O(g)
<h3>Further explanation</h3>
There are several reactions that can occur in a chemical reaction: single replacement, double replacement, synthesis, decomposition or combustion, etc.
1.Al(s)+HCl(aq)⇒AlCl₃(aq)+H₂(g)
type : single replacement
balance :
2Al(s)+6HCl(aq)⇒2AlCl₃(aq)+3H₂(g)
2. AgNO₃ (aq) + Cu (s) ⇒ Cu(NO₃)₂ (aq) + Ag (s)
type : single replacement
balance :
2AgNO₃ (aq) + Cu (s)⇒Cu(NO₃)₂ (aq) + 2Ag (s)
3. C₃H₈O + O₂ ⇒ CO₂ + H₂O
type : combustion of alcohol
balance :
2C₃H₈O(l) + 9O₂(g) ⇒ 6CO₂(g) + 8H₂O(g)
