Brainliesttt ! me : )
analyze your observations of each reaction. based on the products made, were your predictions of chemical reaction type correct? in what other ways could you test your predictions to confirm their accuracy?

Here's what I get.

Explanation:

Fe and CuSO₄

You saw a reddish-brown solid growing on the iron nail and the solution turning green.

That is consistent with a single displacement reaction in which Fe displaces Cu from CuSO₄.

The only question is whether the iron was converted to Fe²⁺ or Fe³⁺.

I think you got Fe²⁺, because Fe²⁺ is pale green while Fe³⁺ is yellow brown in solution.

You could make sure by adding a few drops of KSCN to the green solution. Fe³⁺ would form a blood red colour with SCN⁻ ions.

Pb(NO₃)₂ + KI

You saw a yellow precipitate.

That is consistent with a double replacement reaction as written.

PbI₂ is a bright yellow solid.

Mg + HCl

You saw the evolution of a colourless gas that tested for hydrogen.

That is consistent with a single replacement reaction as written.

Electrolysis of water

You saw the evolution of colourless gases in a 2:1 ratio.

That is consistent with a decomposition reaction as written.

You could have tested to see which gas was hydrogen and which was oxygen.

The hydrogen would give its characteristic "pop" in the presence of a flame, while the pure oxygen would cause a glowing splint to burn brightly.

Burning Mg

You saw that Mg burns much more vigorously in pure oxygen than in air.

That is consistent with a combination reaction as written.

You might have tested if other substances burn faster in pure oxygen. For example, a glowing splint.

i just got this problem. it's 90.3

when 25.0 ml of 0.700 mol/l naoh was mixed in a calorimeter with 25.0 ml of 0.700 mol/l hcl, both initially at 20.0 °c, the temperature increased to 22.1 °c. the heat capacity of the calorimeter is 279 j/°c.

the equation for the reaction is:

naoh + hcl → nacl + h₂o

moles of hcl = 0.0250 l hcl ×

0.700

mol hcl

1 l hcl = 0.0175 mol hcl

volume of solution = (25.0 + 25.0) ml = 50.0 ml

mass of solution = 50.0 ml soln ×

1.00

ml soln

= 50.0 g soln

δt=t2-t1

= (22.1 – 20.0) °c = 2.1 °c

the heats involved are

heat from neutralization + heat to warm solution + heat to warm calorimeter = 0

q1+q2+q3=0

nδh+mcδt+cδt=0

0.0175 mol ×

δh

+ 50.0 g × 4.184 j·g⁻¹°c⁻¹ × 2.1 °c + 279 j°c⁻¹ × 2.1 °c = 0

0.0175 mol ×

δh

+ 439.32 j + 585.9 j = 0

0.0175 mol ×

δh

= -1025.22 j

δh=1025.22j0.0175 mol= -58 600 j/mol = -58.6 kj/mol