Question

1. choose the best answer.

the yellow substance in the test tube shown is called a(n) ______
options: reactant, dissociate, precipitate, spectator

1. balance the double replacement equation by typing the numbers in the blanks. type in 1 if the coefficient is 1.

__ pb(no₃)₂ + k₂s → pbs + __ kno₃

1. balance the double replacement equation by typing the numbers in the blanks. type in 1 if the coefficient is 1.

__ fecl₃ + naoh → fe(oh)₃ + __ nacl

Explanation:

(Question 6):

Step1: Identify the substance type

The yellow solid forms as an insoluble product from mixing solutions, which is a precipitate.

(Question 7):

Step1: Balance Pb atoms

Pb is balanced (1 on each side).

Step2: Balance S atoms

S is balanced (1 on each side).

Step3: Balance K and NO₃⁻

There are 2 K and 2 NO₃⁻ on left, so add 2 to KNO₃.
$$\ce{Pb(NO3)2 + K2S -> PbS + 2KNO3}$$

Step4: Verify all atoms

Pb:1, N:2, O:6, K:2, S:1 on both sides.

(Question 8):

Step1: Balance Fe atoms

Fe is balanced (1 on each side).

Step2: Balance Cl atoms

3 Cl on left, add 3 to NaCl.
$$\ce{FeCl3 + NaOH -> Fe(OH)3 + 3NaCl}$$

Step3: Balance Na atoms

3 Na on right, add 3 to NaOH.
$$\ce{FeCl3 + 3NaOH -> Fe(OH)3 + 3NaCl}$$

Step4: Verify OH⁻ atoms

3 OH⁻ on both sides.

Answer:

(Question 6):
precipitate

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