Số mol chất X ở đktc là: \(n=\dfrac{V}{22,4}=\dfrac{1}{22,4}=0,0446\left(mol\right)\)
\(M_X=\dfrac{m}{n}=\dfrac{1,25}{0,0446}=93\left(\dfrac{g}{mol}\right)\)
\(m_C=\dfrac{93.85,71}{100}=80\left(g\right)\Rightarrow n_C=\dfrac{80}{12}=\)
\(m_H=93-80=13\left(g\right)\)
thui em ko đủ trình :D
cho da thuc A= \(\left(xy^2\right)\left(x^5y^4\right)\left(x^9y^6\right)\left(x^{13}y^8\right)\left(x^{17}y^{10}\right)...\)Biet da thuc A co bac bang 3675 . bac cao nhat cua bien x la...
Xac dinh da thuc f(x) neu :
f(x) = ( x - 2 ) du 5
f(x) = ( x - 3 ) du 7
Chung minh f(x) : ( x - 2 ) ( x - 3 ) duoc thuong la ( x2 - 1 ) con lai .
cho da thuc fx biet fx chia x- 3 du 21, fx chia x+2 du -4, fx chia (x+2)(x-3) bang x^2+4 va con du . tinh phan tu tu do cua fx
biet rang phuong trinh (x-3a+1)(3x+2a-5)=0 (a la tham so nguyen duong ) co mot nghiem x=1 . nghiem con lai cua phuong trinh la x=....
cho biet x=can 2 la 1 nghiem cua phoung trinh: X^3+ax^2+bx+c=0 voi cac he so huu ty. tim ca c nghiem con lai
Tim cac so nguyen x de biet thuc \(A=\dfrac{x^5+1}{x^3+1}\) co gt la so nguyen
cho bieu thuc A=[x+2/x^2-x+x-2/x^2+x].x^2-1/x^2+2
a) tim dieu kien cua x de gia tri cua bieu thuc A duoc xac dinh
b) tinh gia tri cua bieu thuc A voi x = -200
biet rang phuong trinh (x-3a+1)(3x+2a-5)=0 (ala tham songuyen duong) co mot nghiem x=1 . nghiem con lai cua phuong trinh la x=....
tinh gia tri cua bieu thuc:
A=x^2+12x+36 tai x=64
B=x^2+4xy+4y^2 khi biet x=2,8; y=3,6
C=(3x-7)^2+10(3x-7)+25 biet x=16
D=8x^3-12x^2+6x-1 tai x=\(\dfrac{-1}{2}\)
