What is the correct chemical formula for the compound “D” carbonate, where “D” is a cation with a charge of +2 (or 2+)?

Calculate the number of carbon atoms that are present in 42.1 g of pentene, C5H10.

Considering the molecular geometries as predicted by VSEPR, which of the choices below would you expect to be a polar molecule?

What would be the wavelength, in nm, of a photon that has [a] x 10–19 J of energy? Note 1: Do NOT include any unit symbols in your answer. Note 2: If you choose to enter your answer in scientific notation, use the “E” notation, for example 7.2 × 104 would be entered as 7.2E4.

What mass, in grams, of zinc chloride would completely react with [v] mL of a [m] M solution of sodium hydroxide, according to the reaction below? You can use the molar masses: ZnCl2  = 136.315 g/mol NaOH = 39.9971 g/mol Note: Do NOT include any unit symbols in your answer.

What is the name of the covalent compound Si3Cl6?

What will be the output of the following program? [assume new lines appear where needed] for x in range(2, 6):  print(x) 

What is returned by the following function? def check_value(x):   try:    if x > 0:       return “Positive”    elif x == 0:       return “Zero”    else:       return “Negative”   except:       return “—“result = check_value(“Hello”) print (result)

What will be the output of the following program? b = “Hello, World!”print(b[2:5])    

Write a Python program that acts as a very basic calculator. Your program should: Ask the user for two numbers. Ask the user for an operation. (addion + or subtraction -).   Perform the chosen operation on the two numbers and print the result. Include a simple check to make sure only numbers are input. Your program should loop until both numbers entered are zero.  Hint: You will need a loop and a try/except!  Sample run: Enter first number (0 to exit): 10Enter second number (0 to exit): 5Enter operation (+, -,): +Result: 15.0——————————Enter first number (0 to exit): abcInvalid input. Please enter numbers.——————————Enter first number (0 to exit): 0Enter second number (0 to exit): 0Exiting calculator. Goodbye! You should be able to complete this in 17 lines of code or fewer. However, if you go over, no points will be deducted. You do not need to use functions unless you want to.