Answer:
Explanation:
We're asked to calculate the number of atoms of
Ca
in
153
g Ca
.
What we must first do is convert the given mass of calcium to moles of calcium, using its molar mass (referring to a periodic table, this is
40.08
g
mol
):
153
g Ca
(
1
mol Ca
40.08
g Ca
)
=
3.82
mol Ca
Using Avogadro's number,
6.022
×
10
23
particles
mol
, we can calculate the number of atoms present:
3.82
mol Ca
(
6.022
×
10
23
atoms Ca
1
mol Ca
)
=
2.30
×
10
24
atoms Ca
<h2>Answer:</h2>
In both glasses have juices of same mass. But the temperature is different due to which the kinetic energy of molecules in both glasses is different.
As kinetic energy is directly proportional to temperature.
To make the kinetic energy of the molecules equal she should:
- Heat one glass of 25°C to 40°C.
or
- Cool the juice of 40°C to 25°C
The catalyst (4) decreases the activation energy required for a reaction, by holding reactants in place
Answer:
Option B
Explanation:
Magnesium is an alkali earth metal and chlorine is a nonmetal. Due to this, and their differences in electronegativity, the elements form an ionic bond. Since magnesium has two valence electrons, it will give them up to two chlorine atoms (which has 7 valence electrons), which needs them to complete its octet. From this, magnesium forms a cation, and will have the ion formula Mg(2+). The two chlorine atoms form anions, and will have the ion formula Cl(1-).
Terms:
- Cation: a positively charged ion
- Anion: a negatively charge ion.
- Electronegativity: the tendency of an atom in a molecule to attract the shared pair of electrons towards itself.
