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
vivado [14]
3 years ago
10

Which of the following is an example of an observation?

Chemistry
1 answer:
Bess [88]3 years ago
8 0
THE ANSWER TO THE QUESTION IS A
You might be interested in
A sample of hydrogen gas was collected over water at 21ºc and 685 mmhg. the volume of the container was 7.80 l. calculate the m
murzikaleks [220]
To determine the mass of the hydrogen gas that was collected, we calculate for the moles of hydrogen gas from the conditions given. In order to do this, we need an equation which would relate pressure, volume and temperature. For simplicity, we assume the gas is an ideal gas so we use the equation PV = nRT where P is the pressure, V is the volume, n is the number of moles of the gas, T is the temperature and R is the universal gas constant. We calculate as follows:

PV = nRT
n = PV / RT
n = (18.6/760) (7.80) / 0.08205 ( 21 + 273.15)
n = 0.0079 mol

Mass = 0.0079 mol ( 18.02 g / mol ) = 0.1425 g H2
8 0
3 years ago
What is the molarity of a solution containing 45.78gMgCl2 dissolved in 3.00L of solution?
Irina18 [472]

The formula is M (molarity) = mol / liters

molarity = ?

mass = 45.78g of MgCl2

Volume = 3.00L

1/ Convert grams to mol by using the formula:  mol = mass / Molar mass

    a/ Molar mass of MgCl2:

          Mg = 1 x 24.30 = 24.30 g/mol

          Cl = 2 x 35.45 = 70.9 g/mol

    Add them together:

         24.30 g/mol + 70.9 g/mol = 95.2 g/mol

    b/ mol = mass / Molar mass

        mol = 45.78 g / 95.2 g/mol

        mol = 0.4808

        ==> 0.4808 mol of MgCl2

2/ M = ?

   mol = 0.4808 mol of MgCl2

   Volume = 3.00L

M = mol / liters

M = 0.4808 mol / 3.00 L

M = 0.16 mol/L

8 0
3 years ago
The rate constant of a certain reaction is known to obey the Arrhenius equation, and to have an activation energy . If the rate
vovangra [49]

Answer:

K2 = 61.2 M^-1.S^-1

Explanation:

We complete the question fully:

The rate constant of a certain reaction is known to obey the Arrhenius equation, and to have an activation energy Ea = 71.0kJ/mol . If the rate constant of this reaction is 6.7M^(-1)*s^(-1) at 244.0 degrees Celsius, what will the rate constant be at 324.0 degrees Celsius?

Answer is as follows:

The question asks us to calculate the value of the rate constant at a certain temperature, given that it is at a particular value for a particular temperature. We solve the question as follows:

According to Arrhenius equation, the relationship between temperature and activation energy is as follows:

            k = Ae^-(Ea/RT)

where,   k = rate constant

              A = pre-exponential factor

          Ea  = activation energy

             R = gas constant

              T = temperature in kelvin

From the equation, the following was derived for a double temperature problem:

ln(k2/k1) = (-Ea/R) * (1/T1 - 1/T2)

We list out the parameters as follows:

         

      T1= (244 + 273.15) K = 517.15 K

      T2= (324+ 273.15) K =597.15 K

    K1  = 6.7 ,     K2 = ?

         R = 8.314 J/mol K

     Ea = 71.0 kJ/mol = 71000 J/mol

Putting the given values into the above formula as follows:

ln(k2/6.7) = (-71000/8.314) * (1/517.15 - 1/597.15)

lnk2 - 1.902 = 8539.8 * 0.000259

lnK2 = 1.902 + 2.21

lnK2 = 4.114

K2 = e^(4.114)

K2 = 61.2

Hence, K2 = 61.2 (M.S)^-1

7 0
4 years ago
Read 2 more answers
If an object that stands 3 centimeters high is placed 12 centimeters in front of a plane mirror, how far from the mirror is the
ryzh [129]

Answer:

the mirror is 12 cm away from the image

Explanation:

; the image will be virtual and it will form at 12 cm distance behind the mirror.

7 0
3 years ago
At a transform fault boundary
tiny-mole [99]

Answer:

Most of these faults are hidden in the deep ocean, where they offset divergent boundaries in short zigzags resulting from seafloor spreading, the best-known (and most destructive) being those on land at the margins of continental tectonic plates. A transform fault is the only type of strike-slip fault that is classified as a plate boundary.

Explanation:

7 0
3 years ago
Other questions:
  • What word or two-word phrase best describes the shape of the ammonia ( nh3 ) molecule?
    11·1 answer
  • Phosphodiesterase functions Select one: a. as a membrane-bound receptor molecule. b. to inactivate cyclic AMP. c. to attach phos
    10·1 answer
  • "Magnesium has three naturally occurring isotopes: ______A. Mg-24 with mass 24.3050 amu and a natural abundance of 78.99 %, B. M
    10·1 answer
  • Select the more electronegative element in each pair. O F O Br O s O o O N O P O K O Ca
    9·2 answers
  • Given the following information: Mass of proton = 1.00728 amu Mass of neutron = 1.00866 amu Mass of electron = 5.486 × 10^-4 amu
    9·1 answer
  • PLEASE FILL IN THE BLANKS! THANKS!
    8·1 answer
  • With over 6 billion people living on Earth, it is common for two people to have the same DNA.
    13·1 answer
  • Please help pick more then one answer!!!
    9·1 answer
  • Which of these pairs consists of isoelectronic species? select one: a. zn2 and cu2 b. cl– and s c. na and k d. mn2 and ar e. k a
    15·1 answer
  • the carbon canisters are about the size of a 55-gallon drum, how often would replacement be required?
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!