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Questions in chemistry

[Done] Provide some interesting facts about pumice and sandstone.

[Done] Which of the following statements about scientific models is true? A. Models are useful only if you can hold them in your hands. B. Models are useful only if they can be used to explain or make predictions about something. C. Models are useful only if they represent an object, process, or system that is too small to study directly. D. Models are useful only if they represent reality exactly.

[Done] 1. True or false: All matter on Earth contains thermal energy. 2. True or false: The molecules in frozen water are in motion. 3. True or false: Ice is too cold to have thermal energy. 4. Which way will heat flow when ice and water are combined in a glass?

[Done] What is the dew point when the air temperature is [tex]26^\circ \text{C}[/tex] and the relative humidity is 77%?

[Done] Can you look at the picture and tell me that answer ? Thank you

[Done] Melissa burned her hand on the stove. Why did running cold water over her hand make the burn less severe? A. Cold transferred to her hand from the water by convection. B. Cold transferred to her hand from the water by conduction. C. Heat transferred from her hand to the water by convection. D. Heat transferred from her hand to the water by conduction. --- A radiator is attached to a wall on one side of the room. What is the most likely way its heat will warm the air on the other side of the room? A. By conduction B. By convection C. The warm air will sink and condense D. The warm air will rise and condense --- Which of the following is an example of heat transfer by radiation? A. Wind currents B. A lightbulb giving off heat C. Barefoot on a hot sidewalk D. A microwave oven heating food

[Done] How do electrons behave when metals react with non-metals?

[Done] In a chemical reaction, dynamic equilibrium occurs when the rate of the forward reaction becomes precisely equal to the rate of the reverse reaction. All of the following statements are true EXCEPT: A. A dynamic equilibrium occurs when the reaction is more than 50 percent complete. B. In a dynamic equilibrium, reactants are converted to products at the same rate as products become reactants. C. Reactions that reach a dynamic equilibrium are often referred to as reversible reactions. D. Reactions that reach a dynamic equilibrium are shown with a double arrow, to indicate the forward and reverse reactions. E. Reactions that reach equilibrium very close to the end (product side) are usually shown with only one arrow instead of a double arrow, and we say the reaction goes to completion.

[Done] What's the formula for distance?

[Done] If 3.64g of sand is separated from 5.25g of a mixture of salt and sand, what is the percentage of sand in the sample?