18. The set-up below is used to investigate the properties of hydro Copper (0)
Oxide
Dry hydrogen
gas
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i) On the diagram, indicate what is emitted for the reaction to occur
ii) Hydrogen gas is allowed to pass through the tube for some time before it is lit. Expla
iii) Write an equation for the reaction that occurs in the combustion tube
iv) When the reaction is complete, hydrogen gas is passed through the apparatus until
v) What property of hydrogen is being investigated?
vi) What observation confirms the property stated in (v) above?
vii) Why is zinc oxide not used to investigate this property of hydrogen gas?
cool down. Explain

The earth's moon is unusually large. two popular theories of the moon's origin include the "sister world" hypothesis, which states that the moon formed from the same materials as the earth, near enough to the earth that they fell into orbit around each other. a second theory is the "capture" hypothesis, in which the moon formed elsewhere in the solar system, and the earth's gravity pulled it into its orbit. studies of what the moon is made of indicate that some of its materials had to come from the earth or from the same area of the solar system where the earth had formed. at the same time, the moon does not contain much of the material that makes up the earth's core, so the moon could not have formed from the same materials as the earth. how do the two facts above affect the described theories of the moon's origin? a. they show that scientists will never agree on where the moon came from. b. they show that more experiments on moon formation need to be done. c. they show that no theory accounts for the existence of the moon. d. they show that neither theory is complete and entirely correct.

Acurium-245 nucleus is hit with a neutron and changes as shown by the equation. complete the equation by filling in the missing parts. 52

Three cards with holes are arranged in a straight line. a light is shined through the first card’s hole and travels through all three cards. what does this tell you about light rays? a) that light is reflected b) that light is refractive c) that light travels in a straight line d) that light does not travel in a straight line