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Carbon reacts with hydrogen to form methane according to this reaction:   C   + 2H2 –> CH4   Assume you have 20 grams of carbon and 20 grams of hydrogen. Which is the limiting reactant. Show the calculations to support your answer.

3. Más tarde,_____________

1.______  

C.  Después de ir de compras. Emilia has finished shopping and is now speaking with her mother via video chat. Complete the dialogue by choosing the correct verb in each case and conjugating it in the present perfect tense (haber + past participle). (10 points) Modelo- Tú (2. ir / comer)__________en el restaurante de mi padre en tu cumpleaños.  Respuesta: has comido   Emilia: ¡Mamá! ¿Qué tal? ¡Tengo mucho que contarte! Yo (1. ser / estar) ________________ muy feliz durante mis vacaciones. Mamá: ¡Dime! ¿Adónde (2. ir / hacer) ________________ hoy? Emilia: ¡Fui al centro comercial! Luis y yo (3. estudiar / comprar) ________________ algunas cosas. Mamá: ¡Qué bueno! Y después de ir de compras, ¿ustedes (4. hacer / preferir) _______________ algo más? Emilia: No, pero muy pronto vamos a ir a cenar. Yo no (5. ir / probar) ________________ comida panameña, entonces vamos a un restaurante panameña.

Precipitation reactions in which a solid (called a precipitate) is a product, are commonly used to remove certain ions from solution. One such reaction is as follows:   Ba(NO3)2 + Na2SO4  –> BaSO4   + 2NaNO3   How many grams of Na2SO4 are needed to precipitate all the barium ions produced by 83.9 grams of Ba(NO3)2?

Ocean gyres are asymmetrical because of the Coriolis effect.

Elemental bromine gas can be generated by reacting sodium bromide with elemental chlorine. The other product is sodium chloride. Write a balanced chemical equation for this reaction.

Gold has an atomic number of 79 and a mass number of 197. How many protons are in each atom?  [Joe7] How many neutrons are in each atom?  [Joe8] How many electrons surround the nucleus assuming that gold is neutral and has no atomic charge?  [Joe9]

Write the chemical formula for a compound composed of a magnesium ion and a carbonate ion. [red4] Name the compound.  [red5] Is it an ionic or molecular compound?  [red6]

If you have an Avogadro’s number of sodium atoms, what is its mass to two decimal places (show units)?