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Paul [167]
3 years ago
9

Which of these is the best evidence that a chemical reactions occurs when coal burns?

Chemistry
2 answers:
laila [671]3 years ago
3 0

Answer:

It’s b even check quizzes

Explanation:

Rom4ik [11]3 years ago
3 0

Answer:b

Explanation:

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Determine the number of moles of water assicated with the salt.
Nookie1986 [14]

Answer:

Divide the mass of your anhydrous (heated) salt sample by the molar mass of the anhydrous compound to get the number of moles of compound present. In our example, 16 grams / 160 grams per mole = 0.1 moles. Divide the mass of water lost when you heated the salt by the molar mass of water, roughly 18 grams per mole.In order to determine the formula of the hydrate, [Anhydrous Solid⋅xH2O], the number of moles of water per mole of anhydrous solid (x) will be calculated by dividing the number of moles of water by the number of moles of the anhydrous solid (Equation 2.12. 6).

6 0
3 years ago
12. How much mass is in a 3.25-mole sample of NH 4 OH? A. 10.8 g B. 34.0 g C. 35.1 g D. 114 g
Galina-37 [17]

Answer:

D. 114 g

Explanation:

  • NH4OH molecular weight. Molar mass of NH4OH = 35.0458 g/mol This compound is also known as Ammonium Hydroxide.
  • Convert grams NH4OH to moles or moles NH4OH to grams. Molecular weight calculation: 14.0067 + 1.00794*4 + 15.9994 + 1.00794.
8 0
3 years ago
Another name for a "oxidation-reduction" reaction is
anzhelika [568]
Redox (red for reduction and ox for oxidation)
8 0
3 years ago
What is an indicator that a chemical change has occurred?
Aleks04 [339]

Answer:

That something has changed chemically

Explanation:

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6 0
3 years ago
Read 2 more answers
Hot water enters a double-pipe counter-flow water-to-oil heat exchanger at 220°7 and leaves a 100°F. Oil enters at 70°F and leav
il63 [147K]

Answer:

Oil has the smaller heat capacity. The effectiveness of the heat exchanger is 0.80.

Explanation:

Part 1:

In order to know which fluid has the smaller heat capacity we need to consider the heat equation below:

Q = CΔT, where Q is the heat exchanged, C is the heat capacity and ΔT is the variation in temperature.

As the heat exchange is the same for both fluids, the smaller the temperature variation, the smaller the heat capacity.

Water: ΔT = 120 °F  

Oil: ΔT = 80 °F  

Therefore, oil is the fluid with the smallest heat capacity.

Part 2:

The effectiveness of a counter-flow heat exchanger is given by the equation bellow:

E = \frac{Th1 - Th2}{Th1 - Tc1} \\

Th1: initial temperature of the hot fluid

Th2: final temperature of the hot

Tc1: initial temperature of the cold fluid

E = \frac{220 - 100}{220 - 70} \\E = 0.8

7 0
3 years ago
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