What is the name of the compound made from Cu with a 2+ charge and NO4 1-?

What does x represent in the formula for the compound xcl4?

Which of the following describes a situation where competition between producers exists

Polar bears give birth and hunt on sea ice. which of the following would polar bears survive during the melting of arctic ice? growing another layer of fur during summer migrate inland to search for different food sources staying put until the ice refreezes sticking to the usual diet of seals