Is copper wire a mixture or a pure substance?

About 3% of the water on earth is freshest. only about 40% of that freshwater is available for human use. why is so much freshwater unavailable for human use?

The term gas is limited to those substances that exist in the gaseous state at

The standard emf for the cell using the overall cell reaction below is +2.20 v: 2al(s) + 3i2(s) → 2ai3+(aq) + 6i-(aq) the emf generated by the cell when [ai3+] = 3.5 × 10-3 m and [i-] = 0.015 m is v. the standard emf for the cell using the overall cell reaction below is +2.20 v: 2al(s) + 3i2(s) 2ai3+(aq) + 6i-(aq) the emf generated by the cell when [ai3+] = 3.5 × 10-3 m and [i-] = 0.015 m is v. 2.36 2.24 2.21 2.51 2.04