1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
artcher [175]
3 years ago
11

What are two ways to tell if a chemical reaction is taking place?

Chemistry
2 answers:
lorasvet [3.4K]3 years ago
6 0
A chemical reaction is observed by physical effects that cannot be undone, for Ex. If an object give off heat or light, thats a chemical reaction. If theirs a change in an objects color it can be a chemical reaction, like rust. Metal turning silver to brown. <span />
Kruka [31]3 years ago
4 0
1) temperature change
2)odor or smell change
Hope this helps
You might be interested in
One mole of an ideal gas with a volume of 1.0 L and a pressure of 5.0 atm is allowed to expand isothermally into an evacuated bu
Deffense [45]

Answer:

w= - 1.7173 kJ, q= 1.7173 kJ, q(rev) = 1717.3 J = 1.7173 kJ.

Explanation:

Okay, from the question we are given the information below;

Number of moles, n= 1 mole; initial volume, v(1) = 1.0 litres (L); pressure (p) = 5atm, final volume(v2) = 2.0 Litres(L) ; the workdone, w= not given; the heat, q and q(rev)= not given and the gas was said to expand isothermally.

So, this question is a question from the part of chemistry known as thermodynamics. Therefore, grip yourself we are delving into thermodynamics 'waters' now.

For expansion isothermally; the workdone, w= -nRT ln v2/v1.

Where T= temperature= 25° C = 298 k and R= gas constant.

Therefore; workdone, w = - 1 × 8.314 × 298 × ln(2/1).

Workdone,w= - 1717.32204643. =

- 1717.3 Joules (J).

==> Workdone,w= - 1.7173 kJ.

Then, we are to find q. q can be solved by using the first law of thermodynamics, which by mathematical representation is:

∆U= q + w. Where ∆U= change in internal enegy. Since the question is dealing with isothermal expansion, there is this rule that says for an isothermal expansion ∆U = 0.

Hence, 0 =q + [- 1717.3 Joules (J)].

q=1717.3 J = 1.7173 kJ.

Finally, the q(rev) which is= nRT ln (v2/V1).

q(rev) = 1 × 8.314 × 298 ln (2/1).

q(rev) = 1717.3 J = 1.7173 kJ.

PS: please note the negative signs in the workdone and the positive sign in the q(rev).

7 0
3 years ago
19 The coefficients in a balanced chemical equation represent(l ) the mass ratios of the substances in the reaction(2) the mole
Andrews [41]
2. The coefficients represent to molar ratios in a balanced equation.
8 0
3 years ago
The electronegativity of nitrogen (n) is 3.0, while the electronegativity of hydrogen (h) is 2.1. knowing this, consider how the
Goryan [66]

The electronegativity of nitrogen (N) is 3.0, while the electronegativity of hydrogen (H) is 2.1. As it can be seen that nitrogen (N) is more electronegative than that of hydrogen (H),  

So electron pairs are attracted towards nitrogen and thus it carries a partial negative charge and hydrogen carries a partial positive charge. The image of electron distribution is attached as follows.

Thus NH₃ is a polar molecule .

8 0
3 years ago
Which statements are true about Figure I and Figure II below? (Check all that apply)
Scilla [17]

Both figures are mixtures,

Figure II is a heterogenous mixture

Figure I is a homogenous mixture

5 0
3 years ago
Science has shown that air pollution can cause a variety of health issues in our society. Which of the following can be a health
ololo11 [35]
The correct one is Respiratory Distress !!

As rest are not concerned with air pollution !!
8 0
3 years ago
Read 2 more answers
Other questions:
  • What are the two parts of a phospholipid
    10·1 answer
  • Silicones are ________. Select one: A. flat sheets of silicon and hydrogen atoms B. flat sheets of silicon atoms C. chains of al
    7·2 answers
  • Zinc and sulfuric acid solution produce zinc sulfate solution and hydrogen balanced chemical equation
    8·1 answer
  • An element gave off a wavelength of 4.8x10^-7 m. What is the frequency of the element?(needs unit, and 3 sig-figs) *
    14·1 answer
  • (True or False) Only an odd number of orbitals is possible for any electron sublevel?
    13·2 answers
  • Select the answer that CANNOT be used to fill in the blank in the following sentence:
    11·1 answer
  • What does the prefix cis- mean in chemistry
    7·2 answers
  • An unknown gas is contained in a sealed container. Over time, the gas is gradually cooled until it becomes a solid. Determine wh
    8·2 answers
  • The first law of thermodynamics is observed when
    14·1 answer
  • 3. 6 th grade Question
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!