I am having some trouble plotting on Tikz. I want to generate a plot like this,
but instead, my Tikz generates this.
How can I improve my Tikz?
\documentclass[10pt,a4paper]{article}
\usepackage[utf8]{inputenc} % International characters
\usepackage[T1]{fontenc} % Font encoding for international characters
% \usepackage{fouriernc} % Use the New Century Schoolbook font
\usepackage{lmodern} % Use Latin Modern font
% \usepackage{libertine} % Use LLibertine font
% \usepackage{libertinust1math}% Use LLibertine math font
\usepackage{geometry} % Setting page geometry (margins)
\usepackage{blindtext} % Lorem ipsum
\usepackage{textcomp} % For the trademark symbol
\usepackage{booktabs} % Allows the use of \toprule, \midrule and \bottomrule in tables for horizontal lines
\usepackage{siunitx} % Allows for properly formatted numbers with \num{number}, units with \si{unit} and both with \si{number}{unit}
\usepackage{microtype} % A few refinements to typography that are hardly noticeable
\usepackage[normalem]{ulem} %Strikethrough text
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{calc}
%Tables
\usepackage{float} % image positioning
\usepackage{multirow}
\usepackage{array}
\usepackage{tabu}
\usepackage{tikz}
\usepackage{longtable}
\usepackage{caption}
\usepackage{tabularx}
%Itemize
\usepackage{etoolbox,refcount}
\usepackage{multicol}
\usepackage{setspace}
%Fonts
\usepackage{titlesec}
\titleformat{\section}{\normalfont\fontsize{11pt}{11pt}\selectfont\bfseries}{\thesection}{1em}{}
\titleformat*{\subsection}{\normalsize\bfseries}
%Chemistry
\usepackage[version=3]{mhchem}
\usepackage[separate-uncertainty]{siunitx}
\DeclareSIUnit\molar{\mole\per\cubic\deci\metre}
\DeclareSIUnit\Molar{\textsc{M}}
%Page Number
\usepackage{fancyhdr}
\pagestyle{fancy}
\fancyhf{} % clear all header and footer fields
\fancyfoot[R]{\thepage} % page number on right bottom
%Graphs
\usepackage{pgfplots} %Graph
\pgfplotsset{compat=1.5}
\usepackage{graphicx}
\usepackage{adjustbox}
\usepackage{amsmath} % amsmath も必要
\usepackage{mathtools}
\mathtoolsset{showonlyrefs}
% Package must come last
\usepackage[bookmarks=true]{hyperref} % Hyperrefs for bookmarks
\hypersetup{
colorlinks=true,
citecolor=black,
linkcolor=blue,
filecolor=magenta,
urlcolor=blue,
}
\usepackage{bookmark} % Adds metadata to PDF for bookmarking
% Package settings & macros
\renewcommand{\contentsname}{Contents} % Contents heading
\urldef{\usePercentage}\url{%} % Using the percent symbol in documents: \usePercentage
\usepackage[citestyle=authoryear,bibstyle=mla,sorting=nty]{biblatex} % bibliography
\usepackage{url}
\usepackage{appendix}
\renewcommand{\nameyeardelim}{\addcomma\addspace}
\addbibresource{references.bib}
\urlstyle{same}
\renewcommand*{\bibfont}{\scriptsize}
% Document Settings
\geometry{margin=1in}
\setlength{\parskip}{1ex}
\setlength{\parindent}{0pt}
\renewcommand{\headrulewidth}{0pt}
\newlength{\conditionwd}
\newenvironment{conditions}[1][where:]
{%
#1\tabularx{\textwidth-\widthof{#1}}[t]{
>{$}l<{$} @{${}={}$} X@{}
}%
}
{\endtabularx\[\belowdisplayskip]}
\newcounter{countitems}
\newcounter{nextitemizecount}
\newcommand{\setupcountitems}{%
\stepcounter{nextitemizecount}%
\setcounter{countitems}{0}%
\preto\item{\stepcounter{countitems}}%
}
\makeatletter
\newcommand{\computecountitems}{%
\edef@currentlabel{\number\c@countitems}%
\label{countitems@\number\numexpr\value{nextitemizecount}-1\relax}%
}
\newcommand{\nextitemizecount}{%
\getrefnumber{countitems@\number\c@nextitemizecount}%
}
\newcommand{\previtemizecount}{%
\getrefnumber{countitems@\number\numexpr\value{nextitemizecount}-1\relax}%
}
\makeatother
\newenvironment{AutoMultiColItemize}{%
\ifnumcomp{\nextitemizecount}{>}{3}{\begin{multicols}{2}}{}%
\setupcountitems\begin{itemize}}%
{\end{itemize}%
\unskip\computecountitems\ifnumcomp{\previtemizecount}{>}{3}{\end{multicols}}{}}
\begin{document}
\begin{figure}[H]
\caption{the effect of increasing \ce{CuSO4} concentrations on voltage produced}\label{fg:plot}
\begin{center}
\begin{adjustbox}{max width = 200mm}
\begin{tikzpicture}
\pgfplotsset{width=5in, height=4in}
\begin{axis}[
axis lines = left,
xlabel = concentration of \ce{CuSO4} (\si{mol.dm^{-3}}),
ylabel = mean voltage produced (\si{V}),
xmin=-3, xmax=8,
ymin=1.550, ymax=1.950,
xtick={-3.0, -2.0, -1.0, 0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8},
ytick={1.550, 1.600, 1.650, 1.700, 1.750, 1.800, 1.850, 1.900},
legend pos=north west,
]
\addplot [
domain=-2.302585093:6.907755279,
samples=1000,
color=blue,
]
{-0.0301x+1.7967};
\addlegendentry {$-0.0301x+1.7967$}
\addplot[
only marks,
color=blue,
mark=,
error bars/.cd,
y dir=both, y explicit,
x dir=both, x explicit,
]
coordinates {
(6.907755279, 1.586) +- (0, 0)
(4.605170186, 1.662) +- (0, 0)
(2.302585093, 1.732) +- (0, 0)
(0, 1.789) +- (0, 0)
(-2.302585093, 1.869) +- (0, 0)
};
\end{axis}
\end{tikzpicture}
\end{adjustbox}
\end{center}
\end{figure}
\end{document}
