两种气态硼氢化物的化学式和密度如下:BH3在290K和53978Pa时的密度为0.629g·L−1;B2H5在292K和6916Pa时的密度为0.1553g·L−1。这两种化合物的相对分子质量各是多少?写出它们的分子式。

两种气态硼氢化物的化学式和密度如下:BH3在290K和53978Pa时的密度为0.629g·L−1;B2H5在292K和6916Pa时的密度为0.1553g·L−1。这两种化合物的相对分子质量各是多少?写出它们的分子式。


相关考题:

有一过程如下:Sub Sub1(m As Integer,total As Long)Dim i As Integertotal=1For i=1 To mtotal=total*iNextEnd Sub调用它的事件过程如下:Private Sub Command1_Click()Dim tot As Long,a As Integera=Val(InputBox("请输入数据"))Call Sub1(a,tot)Print totEnd Sub则输入数据5,运行结果为【 】。

在通用声明中定义a,在窗体中添加一个命令按钮Command1,编写如下程序代码:DimaAsIntegerSubtest()a=a+1:b=b+1:c=c+1PrintSub:;a;,;b;,;cEndSubPrivateSubCommand1_Click()a=2:b=3:c=4CalltestCalltestEndSub程序运行后,单击命令按钮,窗体中将显示( )A.Sub:3,4,5Sub:4,5,6B.Sub:2,3,4Sub:2,3,4C.Sub:3,1,1Sub:4,1,1D.Sub:1,1,1Sub:1,1,1

有如下SUB过程:Sub s(x As Single,y As Single)t=xx=t / yy=t Mod yEnd Sub在窗体上添加一个命令按钮,然后编写如下事件过程:Private Sub Form_Click()Dim a As SingleDim b As Singlea=5b=4s a,bPrint a,bEnd Sub则程序运行后,单击命令按钮,输出的结果为【 】 。

设程序中有如下数组定义和过程调用语句: Dim a(10)As Integer … Call D(a) 如下过程定义巾,正确的是( )。A.Private Sub p(a As Integer)B.Private Sub p(a( )As Integer)C.Private Sub p(a(10)As Integer)D.Private Sub p(a(n)As Integer)

阅读如下程序, a = 1: b = 2: plus S, a, b: Print S:不能使其输出结果为3的plus过程为( )。 A、Sub plus(sum, a , b ): sum = a + b: End SubB、Sub plus(ByVal sum , a , b ): sum = a + b: End SubC、Sub plus(sum , ByVal a, ByVal b ): sum = a + b: End SubD、Sub plus(sum , ByRef a , ByRef b ): sum = a + b: End Sub

有如下过程:Sub SS(ByVal X,ByRef Y,Z)X=X + 1Y=Y + 1Z=Z + 1End Sub执行该过程的事件过程如下:Private Sub Command1_Click()A = 1B = 2C = 3Call SS(A,B,C) Print A;B;CEnd Sub则该程序的执行结果是【 】。

在窗体中添加一个命令按钮,编写如下程序: Private Sub Subl(p,m,n) p=p+1:m=m+1:n=n+1 Print"subl:";p;m;n End Sub Private Sub Command1_Click() al=1:b=2:c1=3 Call Subl(a,b1+3,c1) Print"Main:";a1;b1;c1 End Sub 程序运行后,输出结果为A.Sub:2 6 4 Main:2 6 4B.Sub:2 6 4 Main:2 6 4C.Sub:2 6 4 Main:1 2 3D.Sub:2 6 4 Main:2 2 3

有如下程序: Private Sub Command1_Click() Dim a As Single Dim b As Single a=5:b=4 Call Sub1(a,b) End Sub Sub Sub1(x As Single,y As Single) t=X X=t\Y Y=t Mod y End Sub 在调用运行上述程序后,a和b的值分别为A.0 0B. 1 1C.2 2D.1 2

有如下一个Sub过程: Sub mlt(ParamArray numbers()) n=1 For Each x In numbers n=n*x Next x Print n End Sub 在一个事件过程中如下调用该Sub过程: Private Sub Command1_Click() Dim a As Integer Dim b As Integer Dim c As Integer Dim d As Integer a=1 b=2 c=3 d=4 mlt a,b,c,d End Sub 该程序的运行结果为( )。A.12B.24C.36D.48

设程序中有如下数组定义和过程调用语句:Dim a(10) as integer……Call p(a)如下过程定义中,正确的是A)Private Sub p(a as integer)B)Private Sub p(a() as integer)C)Private Sub p(a(10) as integer)D)Private Sub p(a(n) as integer)

假定有如下的Sub过程:Sub Sub1(x As Single,y As single)t=xx=t/yy=t Mod yEnd Sub在窗体上画一个命令按钮,然后编写如下事件过程:Private Sub Command1_click()Dim a As SingleDim b As Singlea=5b=4Sub1 a,bPrint a;bEnd Sub程序运行后,单击命令按钮,输出结果为A.B.C.D.

假定有如下的Sub过程:Sub Sub1(x As Single, y As single)t=xx=t / yy=t Mod yEnd Sub在窗体上画一个命令按钮,然后编写如下事件过程:Private Sub Command1_Click()Dim a As SingleDim b As Singlea=5b=4Sub1 a,bPrint a;bEnd Sub程序运行后,单击命令按钮,输出结果为A.54B.] 1]]1C.] 1.2]]5.4D.] 1.25]]1

在窗体上画一个名称为Command1的命令按钮,然后编写如下事件过程: Private Sub Command1_Click() Call sub1(-15.1,2.54) End Sub Public Function sub1(a As Integer,ByVa1 b As String) As Integer a=Val(B)sub1=a Print sub1 End Function 程序运行后,单击命令按钮,在窗体上输出的是A.3B.2C.-15D.提示出错

在窗体上画一个命令按钮,然后编写如下程序: Private Sub Comrnand3_Click( ) Cop 2 Cop 3 Cop 4 End Sub Sub Cop (a As Integer) Static x As Integer x=x + a Print x; End Sub 程序运行后,单击命令按钮,输出结果为A.2 3 4B.2 5 9C.3 5 4D.2 4 3

在窗体中添加一个命令按钮,编写如下程序: Private Sub Test(p,m,n) p=p+1:m=m+1:n=n+1 Print "Sub: ";p;m;n End Sub Private Sub Command1.Click() a1=1:b=2:c1=3 Call Test((a,b1+3,(c1)) Print "Main:";a1;b1;c1 End Sub 程序运行后,输出结果为A.Sub: 2 6 4 Main: 2 6 4B.Sub: 2 6 4 Main: 2 6 4C.Sub: 2 6 4 Main: 1 2 3D.Sub: 2 6 4 Main: 2 2 3

假定有如下的Sub过程:Sub Sub1 (x As Single, y As Single) t=x x = t/y y = t Mod yEnd Sub 在窗体上画一个命令按钮,然后编写如下事件过程:Private Sub Command1_ Click() Dim a As Single Dim b As Single a = 5 b = 4 Sub1 a, b Print a; b End Sub 程序运行后,单击命令按钮,输出结果为______。A.5 4B.1 1C.1.2 5.4D.1.25 1

现有如下Sub过程: Sub fun(x es single,y as single) t = x x = t/y y = t mod y End sub在窗体上添加命令按钮(cmD) ,编写如下事件过程: Private sub cmd_click( ) Dim a as single Dim b as single a = 5 b = 4 fun a, b Msgbox a chr(10) + chr(13) b End sub运行程序后,单击按钮,则在消息框中显示的内容为( )A.1和1B.1.25和1C.1.25和4D.5和4

有如下一个Sub过程: Sub mlt (ParamArray numbers()) n=1 For Each x In numbers n=n * x Next x Print n End Sub在一个事件过程中如下调用该Sub过程: Private Sub Coinmand1_Click() Dim a As Integer Dim b As Integer Dim c As Integer Dim d As Integer a=1 b=2 c=3 d=4 mlt a,b,c,d End Sub 则运行该程序,结果为______。A.12B.24C.36D.48

在窗体中添加一个命令按钮,编写如下程序:Private Sub Sub1(p,m,n)p=p+1:m=m+1:n=n+1Print "sub1:";p;m;nEnd SubPrivate Sub Command1_Click()a1=1:b=2:c1=3Call Sub1(a,b1+3,c1)Print"Main:";a1;b1;c1End Sub程序运行后,输出结果为A.Sub: 2 6 4 Main: 2 6 4B.Sub: 2 6 4 Main: 2 6 4C.Sub: 2 6 4 Main: 1 2 3D.Sub: 2 6 4 Main: 2 2 3

若有如下程序:sub(int a,int b,int *z){*z=a+b;return;}main(){int a=1,b=2,c=3,d,e;sub(a,b, return;} main() {int a=1,b=2,c=3,d,e; sub(a,b,D) ; sub(c,d,e); printf("%d",e); } 则程序运行后的输出结果是A.3B.4C.5D.6

在窗体中添加一个命令按钮,编写如下程序: Private Sub Sub1(p,m,n) p=p+1:m=m+1:n=n+1 Print "sub1:";p;m;n End Sub Private Sub Command1_Click() a1=1:b=2:c1=3 Call Sub1(a,b1+3,c1) Print"Main:";a1;b1;c1 End Sub 程序运行后,输出结果为A.Sub: 2 6 4 Main: 2 6 4B.Sub: 2 6 4 Main: 2 6 4C.Sub: 2 6 4 Main: 1 2 3D.Sub: 2 6 4 Main: 2 2 3

若有如下程序:sub(int a,int b,int*z){*z=a+b;return;}main(){int a=1,b=2,C=3,d,e;sub(a,b,d); sub(C,d,e); printf("%d",e); } 则程序运行后的输出结果是( )。A.3B.4C.5D.6

有如下Sub过程:Sub ind(a As Integer)Static x As Integerx= x + aPrint x:End Sub以下是调用它的事件过程,程序运行后,单击命令按纽Command1三次,输出结果为【 】。Private Sub Command1_Click()Ind 2End Sub

某元素X的气态氢化物的化学式为H2X,则X的最高价氧化物对应的水化物的化学式是 (  )

单选题A pIsub2/sub=Isub3/sub/pB pIsub2/sub=4Isub3/sub/pC pIsub2/sub=2Isub3/sub/pD pIsub3/sub=4Isub2/sub/p

填空题某元素A能形成气态氢化物HxA,此气体在标准状况下的密度为1.639克/摩尔,该气体的水溶液能跟Na2CO3反应放出CO2,反应过程中HxA和Na2CO3物质的量之比为2∶1.  (1)A的气态氢化物的化学式是____.  (2)A的最高正化合价为____,它的最高价氧化物的水化物的化学式为____,它是已知最强的____.

单选题给定子例行程序如下  SUBROUTINE SUB(K,A)  B=K+2  A=A+B END 下列调用语句中正确的是()ACALL SUB(N,N)BCALL SUB(X,X)CCALL SUB(N+2,X)DCALL SUB(N,X+3)