\(n_P=\dfrac{12,4}{31}=0,4\left(mol\right)\)

\(n_{O_2}=\dfrac{18}{32}=0,5625\left(mol\right)\)

PTHH :

\(4P+5O_2\rightarrow\left(t^o\right)2P_2O_5\)

0,4    0,5               0,2

\(\dfrac{0,4}{4}< \dfrac{0,5625}{5}\) --> O2 dư sau phản ứng 

\(m_{O_2dư}=\left(0,5625-0,5\right).32=2\left(g\right)\)

P2O5 được tạo thành.

\(m_{P_2O_5}=0,2.142=28,4\left(g\right)\)

\(n_P=\dfrac{12,4}{31}=0,4\left(mol\right)\)

\(n_{O_2}=\dfrac{18}{32}=0,5625\left(mol\right)\)

PT: \(4P+5O_2\underrightarrow{t^o}2P_2O_5\)

a, Xét tỉ lệ: \(\dfrac{0,4}{4}< \dfrac{0,5625}{5}\), ta được O₂ dư.

Theo PT: \(n_{O_2\left(pư\right)}=\dfrac{5}{4}n_P=0,5\left(mol\right)\Rightarrow n_{O_2\left(dư\right)}=0,0625\left(mol\right)\)

\(\Rightarrow m_{O_2\left(dư\right)}=0,0625.32=2\left(g\right)\)

b, P₂O₅ được tạo thành.

Theo PT: \(n_{P_2O_5}=\dfrac{1}{2}n_P=0,2\left(mol\right)\)

\(\Rightarrow m_{P_2O_5}=0,2.142=28,4\left(g\right)\)

\(a.n_P=\dfrac{12,4}{31}=0,4mol\\ n_{O_2}=\dfrac{18}{32}=0,5625mol\\ 4P+5O_2\rightarrow2P_2O_5\\ \Rightarrow\dfrac{0,4}{4}< \dfrac{0,5625}{5}\Rightarrow O_2.dư\\ n_{O_2,pư}=\dfrac{0,4.5}{4}=0,5mol\\ m_{O_2.dư}=\left(0,5625-0,5\right).32=2g\\ b.Chất.tạo.thành:P_2O_5\\ n_{P_2O_5}=\dfrac{0,4.2}{4}=0,2mol\\ m_{P_2O_5}=0,2.142=28,4g\)

\(n_{O_2}=\dfrac{6.72}{22.4}=0.3\left(mol\right)\)

\(n_{N_2O_5}=\dfrac{10.8}{108}=0.1\left(mol\right)\)

\(2N_2+5O_2\underrightarrow{t^0}2N_2O_5\)

\(.......0.25.....0.1\)

\(m_{O_2\left(dư\right)}=\left(0.3-0.25\right)\cdot32=1.6\left(g\right)\)

nP=\(\dfrac{62}{31}\)=0,2(mol)

nO2=\(\dfrac{7,84}{22,4}\)=0,35(mol)

PTHH:4P+5O2to→2P2O5

tpứ:    0,2     0,35     

pứ:     0,2     0,25     0,1

spứ:     0     0,1         0,1

a)chất còn dư là oxi

mO2dư=0,1.32=3,2(g)

b)mP2O5=n.M=0,1.142=14,2(g)

\(a.n_P=0,2\left(mol\right);n_{O_2}=0,35\left(mol\right)\\ 4P+5O_2-^{t^o}\rightarrow2P_2O_5\\ LTL:\dfrac{0,2}{4}< \dfrac{0,35}{5}\\ \Rightarrow SauphảnứngO_2dư\\ n_{O_2\left(pứ\right)}=\dfrac{5}{4}n_P=0,25\left(mol\right)\\ \Rightarrow m_{P\left(dư\right)}=\left(0,35-0,25\right).32=3,2\left(g\right)\\ b.n_{P_2O_5}=\dfrac{1}{2}n_P=0,1\left(mol\right)\\ \Rightarrow m_{P_2O_5}=0,1.142=14,2\left(g\right)\)

a) n\(_P\) = \(\dfrac{6,2}{31}\) = 0,2(mol); n\(_{O_2}\) = \(\dfrac{7,84}{22,4}\) = 0,35(mol).

Theo phương trình hóa học:

\(4P+5O_2\) \(\underrightarrow{t^o}\) \(2P_2O_5\)

4        5          2 (mol)

0,2 \(\rightarrow\)0,25 \(\rightarrow\) 0,1(mol)

Tỉ lệ số mol: \(\dfrac{0,2}{4}< \dfrac{0,35}{5}\) \(\Rightarrow\) \(O_2\) phản ứng dư, P phản ứng hết.

\(n_{O_2}\)dư = 0,35 - \(\dfrac{0,2.5}{4}\) = 0,1(mol) \(\Rightarrow\) \(m_{O_2}\)dư = 0,1.32 = 3,2g

b) \(n_{P_2O_5}\) = 0,1.142 = 14,2g

\(n_{O_2}=\dfrac{3.36}{22.4}=0.15\left(mol\right)\)

\(4Al+3O_2\underrightarrow{^{t^0}}2Al_2O_3\)

\(0.2.....0.15\)

\(m_{Al}=0.2\cdot27=5.4\left(g\right)\)

Em xem lại yêu cầu đề bài nhé !

\(n_P=\dfrac{3,1}{31}=0,1\left(mol\right)\)

\(n_{O_2}=\dfrac{4,48}{22,4}=0,2mol\)

4P + 5O₂ \(\underrightarrow{t^o}\) 2P₂O₅

\(\dfrac{0,1}{4}< \dfrac{0,2}{5}\) => O₂ dư, Photpho đủ

\(n_{O_2}=0,2-0,04=0,16\left(mol\right)\)

\(m_{P_2O_5}=\) 0,05 . 142 = 7,1 ( g )

Sửa đề: 2,47 (l) → 2,479 (l)

a, \(4P+5O_2\underrightarrow{t^o}2P_2O_5\)

b, Ta có: \(n_P=\dfrac{12,4}{31}=0,4\left(mol\right)\)

\(n_{O_2}=\dfrac{2,479}{24,79}=0,1\left(mol\right)\)

Xét tỉ lệ: \(\dfrac{0,4}{1}>\dfrac{0,1}{5}\), ta được P dư.

Theo PT: \(n_{P\left(pư\right)}=\dfrac{4}{5}n_{O_2}=0,08\left(mol\right)\)

\(\Rightarrow n_{P\left(dư\right)}=0,4-0,08=0,32\left(mol\right)\)

\(\Rightarrow m_{P\left(dư\right)}=0,32.31=9,92\left(g\right)\)

a) $n_{Cu} = \dfrac{12,8}{64} = 0,2(mol)$
$n_{O_2} = \dfrac{33,6.20\%}{22,4} = 0,3(mol)$
$2Cu + O_2 \xrightarrow{t^o} 2CuO$
$n_{Cu} : 2 < n_{O_2} :2$ nên Oxi dư

$n_{CuO} = n_{Cu} = 0,2(mol)$
$m_{CuO} = 0,2.80 = 16(gam)$

b)

$n_{O_2\ pư} = \dfrac{1}{2}n_{Cu} = 0,1(mol)$
$m_{O_2\ dư} = (0,3 - 0,1).32 = 6,4(gam)$

a)

\(n_{Mg} = \dfrac{4,8}{24} = 0,2(mol)\\ n_{O_2} = \dfrac{3,36}{22,4}= 0,15(mol)\\ 2Mg + O_2 \xrightarrow{t^o} 2MgO\)

Ta thấy : 

\( \dfrac{n_{Mg}}{2} = 0,1 < n_{O_2} = 0,15 \) nên O₂ dư.

\(n_{O_2\ pư} = \dfrac{n_{Mg}}{2} = 0,1(mol)\\ m_{O_2\ dư} = (0,15-0,1).32 = 1,6(gam)\\ V_{O_2\ dư} = (0,15-0,1).22,4 = 1,12(lít)\)

b)

\(n_{MgO} = n_{Mg} = 0,2\ mol\\ \Rightarrow m_{MgO} = 0,2.40 = 8\ gam\)

\(n_P=\dfrac{3,1}{31}=0,1\left(mol\right)\\ n_{O_2}=\dfrac{3,2}{32}=0,1\left(mol\right)\\ pthh:4P+5O_2\underrightarrow{t^o}2P_2O_5\\ LTL:\dfrac{0,1}{4}>\dfrac{0,1}{5}\) 
=> P dư 
\(n_{P\left(p\text{ư}\right)}=\dfrac{4}{5}n_{O_2}=0,08\left(mol\right)\\ m_{P\left(d\right)}=\left(0,1-0,08\right).31=0,62\left(g\right)\)

\(n_P=\dfrac{3,1}{31}=0,1\left(mol\right)\\ n_{O_2}=\dfrac{3,2}{32}=0,1\left(mol\right)\)

PTHH: \(4P+5O_2\xrightarrow[]{t^o}2P_2O_5\)

bđ      0,1       0,1

pư     0,08     0,1

spư    0,02     0         

=> P dư

\(m_{P\left(dư\right)}=0,02.31=0,62\left(g\right)\)