Chemistry Challenge Round 4

The earth's core contains liquid nickel and iron at temperatures greater than 4,000 degrees Celsius. What must be true of pure liquid nickel in the earth's core compared to pure liquid nickel made in a factory?

I. They have the same freezing point

II. They have the same number of protons in each atom

III. They react the same

• II only

• I and II only

• I and III only

• I, II, and III

Dmitri Mendeleev created the first modern periodic table, shown on the side, in the late 1800s. How did Mendeleev predict the existence of elements that hadn't been discovered yet?

• He discovered the structure of atoms

• He organized the elements based on patterns of reactivity

• He related atomic number to the charge of an atom's nucleus

• He used X-rays to measure atomic numbers

Silver chloride, AgCl, is a temperature-stable lightweight solid that darkens in sunlight. As a result, AgCl is used in glasses that darken in bright light. What chemical property of AgCl explains its use in glasses?

• It does not dissolve in water

• It reacts to form Ag and Cl atoms in UV light

• Its density is 5.56 g/cm^3

• Its melting point is 455 degrees Celsius

A ball is rolling down a hill. What type of energy is the ball gaining?

I. Kinetic energy

II. Mechanical energy

III. Potential energy

• I only

• III only

• I and II only

• II and III only

Element X reacts similarly to oxygen and has the same number of electron shells as silicon. Based on rows two and three of the periodic table, shown on the side, what is element X?

• Boron

• Carbon

• Nitrogen

• Sulfur

A beam of particles passes between two electrically charged plates. One plate is positively charged and the other plate is negatively charged. The beam travels toward the positive plate, as illustrated in the image on the side. Which particles would be present if the beam bent toward the negative plate?

• Anions

• Cations

• Electrons

• Protons

Which of the objects on the side can hold 3/5 liter of liquid?

• I and II

• III and VI

• V only

• IV only

Which of the following groupings of 3 phase changes can be described as all endothermic?

• condensation, deposition, and freezing

• condensation, melting, and vaporization

• melting, boiling, and sublimation

• melting, freezing, and sublimation

An electron configuration describes the number and location of the electrons in an atom. Which is a possible term in an electron configuration?

• All have the same atomic mass number