Answer:
5.71 g
Explanation:
Step 1: Write the balanced equation
2 K + Cl₂ ⇒ 2 KCl
Step 2: Calculate the moles corresponding to 12.0 g of KCl
The molar mass of KCl is 74.55 g/mol.
12.0 g × 1 mol/74.55 g = 0.161 mol
Step 3: Calculate the moles of Cl₂ needed to produce 0.161 moles of KCl
The molar ratio of Cl₂ to KCl is 1:2. The moles of Cl₂ needed are 1/2 × 0.161 mol = 0.0805 mol
Step 4: Calculate the mass corresponding to 0.0805 moles of Cl₂
The molar mass of Cl₂ is 70.91 g/mol.
0.0805 mol × 70.91 g/mol = 5.71 g
Chemists have developed insulation.
Answer:
Explanation:
Any gas at standard temperature and pressure (STP) has a volume of 22.4 liters per mole or 22.4 L/mol. We can create a proportion with this value.
Multiply both sides of the equation by 6.8 moles of krypton.
The units of moles of krypton will cancel.
The denominator of 1 can be ignored, so this becomes a simple multiplication problem.
If we round to the nearest whole number, the 3 in the tenths place tells us to leave the 2 in the ones place.
6.8 moles of krypton gas at standard temperature and pressure is equal to <u>152 liters</u>.
Answer:
4.81×10¹⁰ atoms.
Explanation:
We'll begin by converting 3.2 pg to Ca to grams (g). This can be obtained as follow:
1 pg = 1×10¯¹² g
Therefore,
3.2 pg = 3.2 pg × 1×10¯¹² g / 1 pg
3.2 pg = 3.2×10¯¹² g
Therefore, 3.2 pg is equivalent to 3.2×10¯¹² g
Next, we shall determine the number of mole in 3.2×10¯¹² g of Ca. This can be obtained as follow:
Mass of Ca = 3.2×10¯¹² g
Molar mass of Ca = 40.08 g/mol
Mole of ca=.?
Mole = mass /molar mass
Mole of Ca = 3.2×10¯¹² / 40.08
Mole of Ca = 7.98×10¯¹⁴ mole.
Finally, we shall determine the number of atoms present in 7.98×10¯¹⁴ mole of Ca. This can be obtained as illustrated below:
From Avogadro's hypothesis,
1 mole of Ca contains 6.02×10²³ atoms.
Therefore, 7.98×10¯¹⁴ mole of Ca will contain = 7.98×10¯¹⁴ × 6.02×10²³ = 4.81×10¹⁰ atoms.
Therefore, 3.2 pg of Ca contains 4.81×10¹⁰ atoms.