johnjehu68

Nootkatone one of the chemicals responsible for the odour and taste of grape fruit, shows a molecular ion a M/E= 218 in its mass spectrum and contains carbons, hydrogen, and oxygen.

Suggest several possible molecular formular for nootkatone. How many degrees of unsaturated (double bonds & rings) are indicated.

What is the theoretical yield of product obtained in the reaction of 3 moles of propene with excess amount of hydrogen gas, using a Pt-Al2O3 catalyst at 343K, given the following balanced equation:

C3H6 + H2 --> C3H8

The reaction is known to follow first order kinetics with rate constant of 0.025 L/mol*s at 343K. What will be the conversion of propene after 15 minutes of reaction time and what will be the corresponding yield of product propane?

Let f(x) be a real valued function defined on the interval [0, 1] such that f(0) = 0 and f(1) = 1. Prove that there exists a point c in the interval (0, 1) such that f(c) = c. (This statement is known as the "Intermediate Value Theorem").

Propose a structure for a molecule with formula C4H6 that meets the following description:

Contains 4sp^2

Please draw structure

C4H6 structure that meets the conditions 1 sp, 2 sp2 and 1 sp3

A+B--> C rate= delta [C]/ delta t = k [A]^a[B]^b

a) Given the initial concentration of each of the reactants,calculate the final concentrations of A, B, and C. Assume thereaction goes to completion. [A]initial= 5.0 x 10^-7 M [B]initial=7.0 x 10^-4M [C]initial= 0

b) Which reagent is in large excess? Is it reasonable to say thatthe concentration of this reagent is a constant?

c) How might you rewrite the rate law to show that the rate of thereaction, run under the conditions given in question 2a, dependsupon the concentration of only one reactant?

d) The rate of the above reaction (using the initial reagentconcentrations given above) was studied monitoring theconcentration change of reactant A. A summary of the data obtainedfrom that study is given below. Based on these experiemntalresults, what is the order of the reaction with respect to thisreactant? Given this new info, rewrite the rate law derived inquestion 2c.

graph one: [reactant] vs. time is a graph of a downward slopingcurve, approaches zero as time goes on.

graph two: ln[reactant] vs. time is a graph of a less dramaticdownward sloping curve, approaches zero as time goes by

graph three: 1/[reactant] vs. time is a graph of a straight linewith a positive slope.

what is physics said in a simple term? and how would i write a 100word essay like that?

How to learn math?

Using the latest flutter version under Android Studio. 

Main dart page got numerous errors - See below link

The entire code (Which contained several pages)listed below in url-

The first one -

import 'package:flutter/material.dart';

What is wrong with that line above?
URL doesn't exist not sure why because it used to work before. For some reason it can't find the package

TextStyle(fontWeight: FontWeight.bold, fontSize: 13, color: Colors.black);
TextStyle not define (huh)? Was working before as well.
The rest of the required create class.
Are you guys able to resolve these error messages?

import 'package:flutter/material.dart';

import 'dart:core';

import 'package:final_project1/second.dart';
//test
void main() {
runApp(const App());
}

const text =
TextStyle(fontWeight: FontWeight.bold, fontSize: 13, color: Colors.black);
//for passing image to second screen

Image pic1 = Image.asset('images/burger.jpg');
Image pic2 = Image.asset('images/chicken.jpg');
Image pic3 = Image.asset('images/fries.jpg');

class App extends StatelessWidget {
const App({Key? key}) : super(key: key);

@override
Widget build(BuildContext context) {
return MaterialApp(
theme: ThemeData.dark(),
debugShowCheckedModeBanner: false,
home: const MyApp(),
);
}
}

// ignore: non_constant_identifier_names
double? SmallPrize, MediumPrize, LargePrize;

// ignore: constant_identifier_names
enum OS { Burger, Chicken_Sandwich, French_Fries }

List<String> list = ['Burger', 'Chicken Sandwich', 'French Fries'];

OS? _os;
String? name;
Image pic = Image.asset('images/burger.jpg');
double? sb, mb, lb, ss, ms, ls, sf, mf, lf;
bool button = true;

class MyApp extends StatefulWidget {
const MyApp({Key? key}) : super(key: key);

@override
State<MyApp> createState() => _MyAppState();
}

String b = 'burger';
String c = 'Chicken Sandwich';
String f = 'French fries';

class _MyAppState extends State<MyApp> {
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
toolbarHeight: 100,
shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(10)),
title: const Text(
'Menu',
style: TextStyle(
fontWeight: FontWeight.bold, fontSize: 30, color: Colors.black),
),
centerTitle: true,
backgroundColor: Colors.deepOrange,
),
body: Column(
mainAxisAlignment: MainAxisAlignment.spaceEvenly,
children: [
Expanded(
child: SizedBox(
width: 300,
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
SizedBox(
height: 100, width: 100, child: ClipOval(child: pic2)),
const SizedBox(width: 20),
Expanded(
child: SizedBox(
child: RadioListTile<OS>(
dense: true,
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10),
side: const BorderSide(
color: Colors.black, width: 3)),
contentPadding: const EdgeInsets.all(0),
tileColor: Colors.deepOrange,
title: Text(
list.elementAt(1),
style: text,
),
value: OS.Chicken_Sandwich,
groupValue: _os,
onChanged: (val) {
setState(() {
SmallPrize = 5.00;
MediumPrize = 7.00;
LargePrize = 9.00;
name = list.elementAt(1);
pic = pic2;
_os = val;
});
},
),
),
),
],
),
),
),
Expanded(
flex: 1,
child: SizedBox(
width: 300,
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
SizedBox(
height: 100, width: 100, child: ClipOval(child: pic1)),
const SizedBox(width: 20),
Expanded(
child: RadioListTile<OS>(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10),
side:
const BorderSide(color: Colors.black, width: 3)),
contentPadding: const EdgeInsets.all(0),
title: Text(
list.first,
style: text,
),
value: OS.Burger,
groupValue: _os,
tileColor: Colors.deepOrange,
onChanged: (val) {
setState(() {
SmallPrize = 5.00;
MediumPrize = 7.00;
LargePrize = 9.00;
name = list.first;
pic = pic1;
_os = val;
});
},
),
),
],
),
),
),
Expanded(
child: SizedBox(
width: 300,
child: Row(
mainAxisAlignment: MainAxisAlignment.center,
children: [
SizedBox(
height: 100, width: 100, child: ClipOval(child: pic3)),
const SizedBox(width: 20),
Expanded(
child: SizedBox(
width: 400,
child: RadioListTile<OS>(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(10),
side: const BorderSide(
color: Colors.black, width: 3)),
contentPadding: const EdgeInsets.all(0),
tileColor: Colors.deepOrange,
title: Text(
list.last,
style: text,
),
value: OS.French_Fries,
groupValue: _os,
onChanged: (val) {
setState(() {
SmallPrize = 2.50;
MediumPrize = 3.50;
LargePrize = 5.00;
name = list.last;
pic = pic3;
_os = val;
});
},
),
),
),
],
),
),
),
GestureDetector(
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => Second(
name_item: name.toString(),
pic: pic,
SmallPrize: SmallPrize,
MediumPrize: MediumPrize,
LargePrize: LargePrize,
),
),
);
},
child: Container(
width: double.infinity,
height: 100,
color: Colors.deepOrange,
child: const Center(
child: Text(
'Proceed',
style: TextStyle(
fontWeight: FontWeight.bold,
fontSize: 20,
color: Colors.black),
),
),
),
),
],
),
);
}
}

What is physics?

prove that the operation +, . are well defined binary operations, and with them Zn is a ring.

proof +_n and *_n are binary operations on Z_n

For flutter 3.3.2 fixed the return statement now having issues with the following lines - lib/main.dart(16,18): error G4127D1E8: The getter '_formkey' isn't defined for the class 'MyAppState'. [D:\form_widget5\build\windows\flutter\flutter_assemble.vcxproj]
lib/main.dart(28,23): error G4127D1E8: The getter 'loginData' isn't defined for the class 'MyAppState'. [D:\form_widget5\build\windows\flutter\flutter_assemble.vcxproj]
lib/main.dart(46,23): error G4127D1E8: The getter 'loginData' isn't defined for the class 'MyAppState'. [D:\form_widget5\build\windows\flutter\flutter_assemble.vcxproj]
lib/main.dart(56,27): error G4127D1E8: The getter '_formkey' isn't defined for the class 'MyAppState'. [D:\form_widget5\build\windows\flutter\flutter_assemble.vcxproj]
lib/main.dart(57,25): error G4127D1E8: The getter '_formkey' isn't defined for the class 'MyAppState'. [D:\form_widget5\build\windows\flutter\flutter_assemble.vcxproj]
lib/main.dart(59,52): error G4127D1E8: The getter 'loginData' isn't defined for the class 'MyAppState'. [D:\form_widget5\build\windows\flutter\flutter_assemble.vcxproj]
lib/main.dart(62,52): error G4127D1E8: The getter 'loginData' isn't defined for the class 'MyAppState'. [D:\form_widget5\build\windows\flutter\flutter_assemble.vcxproj]

Full code listed below

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';

void main() {
runApp(const MyApp());
}

class MyAppState extends State<MyApp>{
@override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
body : Container(
padding : const EdgeInsets.all(50.0),
child : Form(
key: _formkey,
child: Column(
children: [
TextFormField(
keyboardType: TextInputType.emailAddress,
validator: (String? inValue) {
if (inValue?.isEmpty?? true) {
return "Please enter username";
}
return null;
},
onSaved: (String? inValue) {
loginData.username = inValue!;
},
decoration: const InputDecoration(
hintText: "[email protected]",
labelText: "Username (eMail address)"
),
),
TextFormField(
obscureText: true,
validator: (String? inValue) {
if (inValue == null) {
return "Password cannot be null";
} else if (inValue.length < 10) {
return "Password must be >= 10 in length";
}
return null;
},
onSaved: (String? inValue) {
loginData.password = inValue!;
},
decoration: const InputDecoration(
hintText : "Password",
labelText : "Password"
),
),
ElevatedButton(
child : const Text("Log In!"),
onPressed: (){
if (_formkey.currentState!.validate()){
_formkey.currentState!.save();
if (kDebugMode) {
debugPrint ("Username: ${loginData.username}");
}
if (kDebugMode) {
debugPrint ("Password: ${loginData.password}");
}
}
},
),
]
),
),
),
),
);
}
}

class MyApp extends StatefulWidget {
const MyApp({super.key});
@override
MyAppState createState() => MyAppState();
}

class LoginData {
String username = "";
String password = "";
}

A 75- snowboarder has an initial velocity of 5.0 at the top of a 28 incline. After sliding down the 110- long incline (on which the coefficient of kinetic friction is = 0.18), the snowboarder has attained a velocity . The snowboarder then slides along a flat surface (on which = 0.15) and comes to rest after a distance .

• You are on top of a snowy mountain on a snowboard. You need a little push by your friend in order to start sliding.

The coefficient of static friction between the snow and the snowboard is 0.1 and assume your normal force is 800N.

Find the net force if your friend was to push you to the right with a force of 80N.

A graduated cylinder was filled with water to the 15.4 mL mark and weighed on a balance. Its mass was 32.12 g. An object made of silver was placed in the cylinder and completely submerged in the water. The water level rose to 17.9 mL. When reweighed, the cylinder, water, and silver object had a total mass of 58.37 g. Calculate the density of silver in g/cm^3.

A 50.0 g silver object and a 50.0 g gold object are both added to 75.5 ml of water contained in a graduated cylinder what is the new water level in the cylinder?

the level of water ina graduated cylinder is 24.8 ml. An object is dropped into the water ande the new water level is 26.8ml. what is the volume of the object?

1. Jack is trying to use a graduated cylinder to measure volume. He puts 75 ml of water into the graduated cylinder. He then places his object into the graduated cylinder. The water level is now 107 ml. What is the volume of Jack's object? How did you figure this out? (Show your work)

An owl has a mass of 4 kg. It dives to catch a mouse, losing 800 J of its GPE. What was the starting height of the owl, in meters?

F varies directly with m m and inversely with the square of d. If d=3 when m=360 and F=160, find d when m=720 and F=80.

Preparing Buffers!

Molecular weights:

NaH2PO4: 119.96 g/mol

Na2HPO4: 141.96 g/mol

Tris base: 121.14 g/mol

Tris-HCl: 157.60 g/mol

Sodium acetate: 58.04 g/mol

pKa:

Tris: 8.30

Phosphate: 7.21

Acetate: 4.76

1) Prepare 750 mL of 0.5 M phosphate buffer, pH 6.7. You have available both NaH2PO4 and Na2HPO4.

2) Prepare 750 mL of 0.5 M phosphate buffer, pH 7.8. You have available Na2HPO4, 6 M NaOH and 6 M HCl.

3) Prepare 750 mL of 0.5 M phosphate buffer, pH 7.2. You have available NaH2PO4, 6 M NaOH and 6 M HCl.

4) Prepare 1.5 L of 300 mM Tris buffer, pH 8.2. You have available both Tris base and Tris-HCl.

5) Prepare 1.5 L of 300 mM Tris buffer, pH 7.8. You have available Tris base, 6 M NaOH and 6 M HCl.

6) Prepare 1.5 L of 300 mM Tris buffer, pH 8.8. You have available Tris-HCl, 6 M NaOH and 6 M HCl.

7) Prepare 500 mL of 3.0 M acetate buffer, pH 5.0. You have available both glacial acetic acid and sodium acetate (note: glacial acetic acid is 17.5 M).

8) Prepare 1L of 50 mM phosphate buffer at pH 7.50 using only Na2HPO4 and 1M HCl.

The pKa of Acetic Acid is 4.76. How many mL of 0.5 M sodium acetate should be added to 100 mL of 0.5 M acetic acid to make a buffer of pH 5.1? What is the molarity of the resulting buffer with respect to acetate (acetate + acetic acid

a. 0.5 M sodium acetate/0.5 M acetic acid
b. 0.5 M ammonium chloride/0.5 M ammonia
c. 0.5 M sodium dihydrogen phosphate/0.5 M hydrogen phosphate

A can of paint that covers 20 ? costs $24.60. The walls of a room 13 ft x 18 ft are 8 ft high.

What is the cost of paint for the walls?

Show all work

A two-gram sample of a red-colored liquid is found to have a volume of four cubic centimeters. Calculate the liquid's density using the following uncertainty specifications, and express your answers in scientific notation.

a) 2.00 g and 4.000 cm3  

b) 2.0000 g and 4.000 

One beaker contains 10.0 mL of acetic acid/sodium acetate buffer at maximum buffer capacity (equal concentrations of acetic acid and sodium acetate), and another contains 10.0 mL of pure water. Calculate the hydronium ion concentration and the pH after the addition of 0.25 mL of 0.10 M HCl to each one. What accounts for the difference in the hydronium ion concentrations?

A. Onebeaker contains 10.0 mL of acetic acid/sodium acetate buffer atmaximum buffer capacity (equal concentrations of acetic acid andsodium acetate), and another contains 10.0 mL of pure water.Calculate the hydronium ion concentration and the pH after theaddition of 0.25 mL of 0.10 M HCl to each one. What accounts forthe difference in the hydronium ion concentrations? Explain thisbased on equilibrium concepts; in other words, saying that

One beaker contains 10.0 mL of acetic acid/sodium acetate buffer at maximum buffer capacity (equal concentrations of acetic acid and sodium acetate), and another contains 10.0 mL of pure water. Calculate the hydronium ion concentration and the pH after the addition of 0.25 mL of 0.10 M HCl to each one. What accounts for the difference in the hydronium ion concentrations? Explain this based on equilibrium concepts; in other words, saying that “one solution is a buffer” is not sufficient. H3O+(aq) + C2H3O2-(aq) ⇄ HC2H3O2(aq) +H2O Ka of acetic acid = 1.8 x 10-5 Acetic acid/sodium acetate buffer: Acetic acid = 0.1M, Sodium acetate = 0.1M

show work

Calculate the concentrations of acetic acid and acetate in the buffer solution:

6 mL of pH 4 buffer solution

6 mL of pH 7 buffer solution

I'm not sure where to start this; do I work backward to find [OH-] and [H3O+] by using 10^-pH?

Thank you.

We are observing wasted heat in everyday life for example in Pakistan heavy generated are installed, during their supply of electricity an excessive amount of wasted heat is produced in its surrounding, similarly when we drive a vehicle a heat is available in the surrounding of engine of that vehicle, we can also see many more such examples of wastage of heat. This heat is effecting the environment of Pakistan badly.

Is it conceivable to convert this wasted heat into some useful work/energy/electricity or not. If yes how? If no why?

“We are observing wasted heat in everyday life for example in Pakistan heavy generated are installed, during their supply of electricity an excessive amount of wasted heat is produced in its surrounding, similarly when we drive a vehicle a heat is available in the surrounding of engine of that vehicle, we can also see many more such examples of wastage of heat. This heat is effecting the environment of Pakistan badly.

Is it conceivable to convert this wasted heat into some useful work/energy/electricity or not. If yes how? If no why?”

Write In 100 words.