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Charra [1.4K]
4 years ago
10

Which statement about polymers is true? A. Polymers are substances that have relatively large molecules. B. Oil and gas are the

starting materials for making all polymers. C. Fabrics such as cotton and silk are synthetic polymers. D. All polymers are obtained from living organisms.
Chemistry
1 answer:
igor_vitrenko [27]4 years ago
3 0

Answer:

A.) Polymers are substances that have relatively large molecules

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Assume that a daily diet of 2000 calories (i.e. 8.37 x 106 J) is converted completely to body heat.
slava [35]

Answer:

(a) the mass of the water is 3704 g

(b) the mass of the water is 199, 285.7 g

Explanation:

Given;

Quantity of heat, H= 8.37 x 10⁶ J

Part (a) mass of water (as sweat) need to evaporate to cool that person off

Latent heat of vaporization of water, Lvap. = 2.26 x 10⁶ J/kg

H = m x Lvap.

m = \frac{H}{L._{vap}} =\frac{8.37 * 10^6.J}{2.26*10^6\ \frac{J}{kg}} = 3.704 \ kg

mass in gram ⇒ 3.704 kg x 1000g = 3704 g

Part (b) quantity of water raised from 25.0 °C to 35.0 °C by 8.37 x 10⁶ J

specific heat capacity of water, C, 4200 J/kg.°C

H = mcΔθ

where;

Δθ is the change in temperature = 35 - 25 = 10°C

m =\frac{H}{c* \delta \theta} = \frac{8.37 *10^6}{4200*10} = 199.2857 kg

mass in gram ⇒ 199.2857 kg x 1000 g = 199285.7 g

5 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
Even though the neighborhood shown by the green star was not next to any of these fires, how was the neighborhood affected by th
iogann1982 [59]
Im pretty sure the answers b

7 0
3 years ago
Read 2 more answers
What is the basic SI unit of time
aniked [119]

Answer:

The base unit for time is the second the other SI units are: metre for length, kilogram for mass, ampere for electric current, kelvin for temperature, candela for luminous intensity, and mole for the amount of substance!

Explanation:

I hope i helped =)

5 0
3 years ago
Based on the graph of US population and steel consumption, what could have led to the increase in steel consumption seen
polet [3.4K]

Answer:

A. Whenever the population has increased, steel consumption has increased as well.

Explanation:

Based on the graph of US population and steel consumption, what could have led to the increase in steel consumption seen  on the graph is that whenever the population has increased, steel consumption has increased as well.

A critical look at the graph, you will discover that the population and the steel consumption are moving upwards (i.e they are increasing). It's seen that as the population increases, steel consumption increases. This is true because as the population increases, people are building houses, more transportation systems that require steel are being manufactured, more household utensils that are steel products are being fabricated etc; therefore the consumption of steel increases.

6 0
3 years ago
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