Chukkei HaElokim – Statutes Before Sinai?

Introduction

What Laws?

Prior to the Decalogue, the only commandment explicitly given to the Children of Israel was the observance of Shabbat. Yet, Moshe, in describing his responsibilities to Yitro in 18:16, includes "וְהוֹדַעְתִּי אֶת חֻקֵּי הָאֱלֹהִים וְאֶת תּוֹרֹתָיו", and Yitro reflects this back a couple of verses later "וְהִזְהַרְתָּה אֶתְהֶם אֶת הַחֻקִּים וְאֶת הַתּוֹרֹת". To what statutes and laws do Moshe and Yitro refer?

"חֻקִּים" / "תּוֹרֹת"

The Torah employs various terms to refer to categories of laws – see חק for analysis of the relationships between different terms. Why do Moshe and Yitro employ dual terminology? Do the terms "חֻקִּים" and "תּוֹרֹת" used here refer to a single set of laws or to multiple groups? To which laws do they refer?