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
Vladimir [108]
3 years ago
13

This is how platinum appears in the periodic table.A purple box has P t at the center and 78 above. Below it says platinum and b

elow that 195.08. Rounded to the nearest whole number, what is the atomic mass of platinum? 78 117 195 273
Chemistry
2 answers:
ozzi3 years ago
6 0

Answer:

3.) 195

Explanation:

Because platinum is 195.079 amu (its on the periodic table)

grigory [225]3 years ago
3 0

Answer:

the answer is 195

Explanation:

You might be interested in
Assign oxidation numbers to the element in each of the following compounds. Remember an oxidation number is for one atom of the
worty [1.4K]

Answer:

a.  x = + 2

b.  x = + 3

c.  x = + 2

d.  x = + 3

Explanation:

The oxidation number is a formal charge assigned to an atom present in a molecule or formula unit or ion based on some arbitrary rules.

a.

<u>Hg</u>O

The oxidation number of Hg in HgO is:

x + (-2) = 0

x = +2

b.

<u>Al₄</u>C₃

The oxidation number of Al in Al<u>₄</u>C₃ is:

4x +(3 × -4) = 0

4x - 12 = 0

4x = +12

x = 12/4

x = +3

c. CrF₂

x + ( 2 × - 1) = 0

x - 2 = 0

x = + 2

d. Fe₂S₃

2x + ( 3 × - 2) = 0

2x + (-6) = 0

2x = 6

x = 6/2

x = +3

7 0
3 years ago
Objects that can bew seen only under magnification
timofeeve [1]
The answer is (D) microscopic. You can remember this, because the name is very close to "microscope," an instrument used to greatly magnify and observe tiny organisms and objects.
4 0
3 years ago
C. Use Hess's law and the following equations to calculate ΔH for the reaction 4NH3 (g) + 5O2 (g) 4NO(g) + 6H2 O(g). Show your w
Monica [59]

Considering the Hess's Law, the enthalpy change for the reaction is -906.4 kJ/mol.

<h3>Hess's Law</h3>

Hess's Law indicates that the enthalpy change in a chemical reaction will be the same whether it occurs in a single stage or in several stages. That is, the sum of the ∆H of each stage of the reaction will give us a value equal to the ∆H of the reaction when it occurs in a single stage.

<h3>ΔH in this case</h3>

In this case you want to calculate the enthalpy change of:

4 NH₃ + 5 O₂ → 4 NO + 6 H₂O

which occurs in three stages.

You know the following reactions, with their corresponding enthalpies:

Equation 1: 2 N₂ + 6 H₂ → 4 NH₃   ΔH = –183.6 kJ/mol

Equation 2:  2 N₂ + 2 O₂ → 4 NO     ΔH = 361.1 kJ/mol

Equation 3: 2 H₂ + O₂→ 2 H₂O     ΔH = -483.7 kJ/mol

Because of the way formation reactions are defined, any chemical reaction can be written as a combination of formation reactions, some going forward and some going back.

In this case, first, to obtain the enthalpy of the desired chemical reaction you need 4 moles of NH₃ on reactant side and it is present in first equation on product side. So you need to invert the reaction, and when an equation is inverted, the sign of delta H also changes.

Now, 4 moles of NO must be a product and is present in the second equation, so let's write this as such.

Finally, you need 6 moles of H₂O on the product side, so you need to multiply by 3 the third equation to obtain the amount of water that you need. Since enthalpy is an extensive property, that is, it depends on the amount of matter present, since the equation is multiply by 3, the variation of enthalpy also.

In summary, you know that three equations with their corresponding enthalpies are:

Equation 1: 2 4 NH₃ → N₂ + 6 H₂  ΔH = 183.6 kJ/mol

Equation 2:  2 N₂ + 2 O₂ → 4 NO     ΔH = 361.1 kJ/mol

Equation 3: 6 H₂ + 3 O₂→ 6 H₂O     ΔH = -1,451.1 kJ/mol

Adding or canceling the reactants and products as appropriate, and adding the enthalpies algebraically, you obtain:

4 NH₃ + 5 O₂ → 4 NO + 6 H₂O ΔH= -906.4 kJ/mol

Finally, the enthalpy change for the reaction is -906.4 kJ/mol.

Learn more about Hess's law:

brainly.com/question/5976752

brainly.com/question/13707449

brainly.com/question/13707449

brainly.com/question/6263007

brainly.com/question/14641878

brainly.com/question/2912965

#SPJ1

7 0
2 years ago
You wish to make a 0.285 M hydroiodic acid solution from a stock solution of 12.0 M hydroiodic acid. How much concentrated acid
Inessa05 [86]

The amount, in mL, of the concentrated acid required, would be 1.1875 mL

<h3>Dilution</h3>

From the dilution equation:

m1v1=m2v2 where m1 and m2 = molarity before and after dilution, and v1 and v2 = volume before and after dilution.

m2 = 0.285M, m1 = 12.0M v2 = 50.0 mL

v1 = m2v2/m1 = 0.285x50/12 = 1.1875 mL

Thus, 1.1875 mL of the acid would be taken and diluted with water up to the 50 mL mark.

More on dilution can be found here: brainly.com/question/13949222

#SPJ1

4 0
2 years ago
think about the statement "there is no new water on earth" write at least 5 sentences describing how there can be no new water o
Vinil7 [7]
Earth contains huge quantities of water in its oceans, lakes, rivers, the atmosphere, and believe it or not, in the rocks of the inner Earth. Over millions of years, much of this water is recycled between the inner Earth, the oceans and rivers, and the atmosphere. This cycling process means that freshwater is constantly made available to Earth's surface where we all live. Our planet is also very efficient at keeping this water. Water, as a vapor in our atmosphere, could potentially escape into space from Earth. But the water doesn't escape because certain regions of the atmosphere are extremely cold. (At an altitude of 15 kilometers, for example, the temperature of the atmosphere is as low as -60° Celsius!) At this frigid temperature, water forms solid crystals that fall back to Earth's surface.
Many people live faraway from freshwater sources. They need to carry their water home.
While our planet as a whole may never run out of water, it's important to remember that clean freshwater is not always available where and when humans need it. In fact, half of the world's freshwater can be found in only six countries. More than a billion people live without enough safe, clean water.
Also, every drop of water that we use continues through the water cycle. Stuff we put down the drain ends up in someone or something else's water. We can help protect the quality of our planet's freshwater by using it more wisely.
8 0
3 years ago
Other questions:
  • The unit "troy ounce" is often used for precious metals such as gold (Au) and platinum (Pt) (1 troy ounce= 31.103 g). (a) A gold
    14·1 answer
  • The shiny appearance of a metal is most closely related to the metal's
    9·2 answers
  • What visible evidence indicates that a solution is saturated?
    15·2 answers
  • Can you help me solve these using "typical” metric conversions <br> (?/?)(?/?)
    11·1 answer
  • Describe a procedure to separate a mixture of sugar, black pepper, and pebbles.
    12·1 answer
  • When a radioactive decay occurs what is released?
    10·1 answer
  • TIMED TEST PLEASE HURRY!!! The development of a new experimental method is most likely to change a theory if it makes it possibl
    14·2 answers
  • Explain how tectonic plates move relative to one another at a transform plate boundary
    11·1 answer
  • 3. What is the primary consumer in the following food chain, sun - tomato plant - tomato worm - wasp?
    6·2 answers
  • What coefficient would balance the following equation ch4+_O2--&gt; CO2+2H2O
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!