Describe in one sentence how fireworks get their color.

Given the reactions, X (s) + 1 2 O 2 (g) ⟶ XO (s) Δ H = - 607.3 kJ XCO 3 (s) ⟶ XO (s) + CO 2 (g) Δ H = + 356.9 kJ what is Δ H for this reaction? X (s) + 1 2 O 2 (g) + CO 2 (g) ⟶ XCO 3 (s)

Which piece of evidence would prove that a reaction is exothermic

Which is an example of an electrolytic cell? a battery a fuel cell a rechargeable battery a spontaneous reaction between lithium and copper

Which of these refers to atoms with the same atomic number but different atomic masses? a. These atoms have different numbers of protons. b. These atoms have different numbers of electrons. c. These atoms are isomers. d. These atoms are isotopes. e.

Which of the following statements about stars is true? All stars are the same age. Stars vary greatly in age. none of these Stars rarely differ in age.

Give 3-5 pieces of evidence to support why cloning is bad.

Nitrogen combines with oxygen to form nitrogen monoxide (no) and nitrogen dioxide (no2). a sample of no consists of 1.14 g of oxygen and 1 g of nitrogen.

The modern periodic table reflects many improvements to Mendeleev's original table. If Mendeleev's table was incorrect, why is it still studied in chemistry classrooms today?

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Explain how the nettle is adapted for defence and protection