Answer:
c = 0.043 j/ g. °C
Explanation:
Given data:
Amount of sample = 500 g
Initial temperature = 55.0°C
Final temperature = 25.0°C
Heat required released = 640 J
Specific heat capacity of sample = ?
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 25°C - 55°C
ΔT = -30°C
by putting values,
-640 J = 500 g × c × -30 °C
c = 640 J / 500 g× 30 °C
c = 640 J /15000 g. °C
c = 0.043 j/ g. °C
b. Polar covalent bonds. The polar N-H bonds hold the NH3 molecules together. They are <em>intramolecular forces</em> of attraction <em>within a molecule</em>.
All the other options are <em>wrong</em>. They are <em>intermolecular forces</em> — the attractive forces <em>between different molecules</em>.
Answer:
(a) Dissolving sugar in water ⇒ physical change
(b) Crushing rock salt ⇒ physical change
(c) Burning sulfur ⇒ chemical change
(d) Digesting a chili dog ⇒ chemical change
Explanation:
<em>Physical changes</em> are those in which the substance does not alter its composition. They only involve changes of states of matter and the chemical substance is stil the same after the change occurs. By other hand, <em>chemical changes</em> are those in which new subtances are formed. So, the subtance is not the same after the change.
(a) Dissolving sugar in water ⇒ <em>physical change</em>; because we obtain a solution of sugar in water (sugar is stil sugar).
(b) Crushing rock salt ⇒ <em>physical change</em>; because we obtain crushed salt, but the chemical composition of the salt is not altered.
(c) Burning sulfur ⇒ <em>chemical change</em>; because sulfur is oxidized (chemical reaction) and new compounds are formed, for example sulfur dioxide.
(d) Digesting a chili dog ⇒ <em>chemical change</em>; because the digestion process is produced by the action of hydrocloric acid, and new compounds are formed.
Answer: true
Viewed simply, electrons are arranged in shells around an atom's nucleus. Electrons closest to the nucleus will have the lowest energy. Electrons further away from the nucleus will have higher energy. An atom's electron shell can accommodate 2n2 electrons (where n is the shell level).
Answer:
magnesium sulfate + water + carbon dioxide
Explanation: