chem
what is matter？
something has mass and takes up space（volume）
What is the black plague?
The Black Plague (most commonly known as the Black Death) was a devastating global pandemic of bubonic plague that struck Europe and Asia in the mid-1300s (specifically peaking in Europe between 1347 and 1351).
It is widely considered the most fatal pandemic in recorded human history, wiping out an estimated 75 to 200 million people across Eurasia and North Africa. In Europe alone, it killed roughly 30% to 60% of the entire population.
What’s the difference between physical change and chemical change?
physical: meting ice chemical: veneer reacting with baking soda
What does the black slaves do after getting sell to the South American?
Enslaved Africans sold into South America were forced into grueling, often fatal labor on sugar, coffee, and cocoa plantations, as well as in gold and diamond mines, urban trades, and domestic service.
What is a kmt and how does particles behave in each state?
**KMT** states that matter is made of constantly moving particles: **solids** vibrate in place, **liquids** slide and flow past each other, and **gases** fly around randomly at high speeds.
What’s the first crusade?
The First Crusade (1096–1099) was the first in a series of medieval religious wars launched by European Christians with the primary goal of recovering the Holy Land, particularly Jerusalem, from Islamic rule.
Using the laboratory data below, determine the molecular formula and deduce the exact structural formula (IUPAC name) of this compound.
### 🏆 Final Answers
1. **Empirical Formula:** \text{C}_8\text{H}_{16}\text{O}_3
2. **Molecular Formula:** \text{C}_{11}\text{H}_{20}\text{O}_3
3. **IUPAC Name:** 2-tert-butyl-2-hydroxy-3,3-dimethylpentanoic acid
What revolutionary technology, invented around 1440 by Johannes Gutenberg, triggered a massive explosion in European literacy and allowed Renaissance humanism and scientific ideas to spread rapidly across the continent?
The invention was the movable-type printing press, which completely transformed how information was shared by making the mass production of books fast, affordable, and accessible to the public.
why does density matters?
Without density, we wouldn't have predictable weather, tectonic activity, floating boats, or a way to easily identify materials. It is nature’s ultimate sorting mechanism.
What devastating military conflict, lasting from 1337 to 1453 between the royal houses of England and France, fundamentally transformed medieval warfare through the introduction of the longbow and gunpowder artillery?
The conflict was the Hundred Years' War, a prolonged struggle that ultimately crippled feudalism, sparked early national identities for both nations, and famously featured the peasant-turned-military leader Joan of Arc.