Answer:
34.8 g
Explanation:
Answer:
We have the masses of two reactants, so this is a limiting reactant problem.
We will need a balanced equation with masses, moles, and molar masses of the compounds involved.
1. Gather all the information in one place with molar masses above the formulas and masses below them.
Mᵣ: 123.90 70.91 208.24
P₄ + 20Cl₂ ⟶ 4PCl₅
Mass/g: 46.0 32.0
2. Calculate the moles of each reactant
3. Calculate the moles of PCl₅ we can obtain from each reactant
From P₄:
The molar ratio is 4 mol PCl₅:4 mol P₄
From Cl₂:
The molar ratio is 4 mol PCl₅:20 mol Cl₂
4. Identify the limiting and excess reactants
The limiting reactant is chlorine, because it gives the smaller amount of PCl₅.
The excess reactant is phosphorus.
5. Mass of excess reactant
(a) Moles of P₄ reacted
The molar ratio is 1 mol P₄:20 mol Cl₂
(b) Mass of P₄ reacted
(c) Mass of P₄ remaining
Mass remaining = original mass – mass reacted = (46.0 - 11.18) g = 34.8 g P₄
Answer : Option B) Lead
Explanation : Lead is chemical element which damages<span> the central nervous system, cardiovascular system, reproductive system, hematological system, and kidneys with overexposure as compared to other elements in the given option.</span>
Answer:
(1) 0.0016 mol/L
Explanation:
Let the concentration of alcohol after 3.5 hours be y M
The reaction follows a first-order
Rate = ky^0 = change in concentration/time
k = 6.4×10^-5 mol/L.min
Initial concentration = 0.015 M
Concentration after 3.5 hours = y M
Time = 3.5 hours = 3.5×60 = 210 min
6.4×10^-5y^0 = 0.015-y/210
y^0 = 1
0.015-y = 6.4×10^-5 × 210
0.015-y = 0.01344
y = 0.015 - 0.01344 = 0.00156 = 0.0016 mol/L (to 4 decimal places)
CH4 + 2O2 -> 2H2O + CO2
You need to add a 2 in front of the O2 and H2O in order to balance the equation.
Explanation:
The mechanisms by which amorphous intermediates transform into crystalline materials are poorly understood. Currently, attracting enormous interest is the crystallization of amorphous calcium carbonate, a key intermediary in synthetic, biological, and environmental systems. Here we attempt to unify many contrasting and contradictory studies by investigating this process in detail. We show that amorphous calcium carbonate can dehydrate before crystallizing, both in solution and in air, while thermal analyses and solid-state nuclear magnetic resonance measurements reveal that its water is present in distinct environments. Loss of the final water fraction—comprising less than 15% of the total—then triggers crystallization. The high activation energy of this step suggests that it occurs by partial dissolution/recrystallization, mediated by surface water, and the majority of the particle then crystallizes by a solid-state transformation. Such mechanisms are likely to be widespread in solid-state reactions and their characterization will facilitate greater control over these processes.
