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3 years ago

Migraine Study Results

2 answers:

6 0

It was used as a placebo (fake) to trick the group into believing they were receiving the medication.
Hope this helps!<span />

salantis [7]3 years ago

4 0

Answer:A Control Group

Explanation:

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How do the particles in each state of matter move

hodyreva [135]

the particles of solids move but very slowly.

the particles of liquids move moderately fast

the particles of gas move very fast.

The reasons for this movement is the space the particles are together. Since there is not move space between solids, the particles move slowly, water there is moderate space, and air there is a lot of space.

7 0

3 years ago

1. An electric power plant uses energy from burning coal to generate steam at 450 °C. The plant is cooled by 20 °C water

kap26 [50]

Answer:

Explanation:

Efficiency of the electric power plant is $e=1-\frac{T_{2}}{T_{1}}$

Here Temperature of hot source $T_{1} = 450^{o}C=450+273=723 K$

and Temperature of sink $T_{1} = 20^{o}C=20+273=293 K$

Hence the efficiency is $e=1-\frac{293}{723}=0.5947=59.47%$

Now another formula for thermal efficiency Is

$e_{therm}=\frac{Q_{1}-Q_{2}}{Q_{1}}=\frac{W}{Q_{1}}$

Here QI is the of heat taken from source 100 MJ ; Q2 of heat transferred to the sink (river) to be found

W is the of work done and W = QI -Q2

Hence From $e_{therm}=\frac{Q_{1}-Q_{2}}{Q_{1}}=\frac{W}{Q_{1}}$

$W=e(Q_{1})=(0.5947)(100)=59.47MJ$

Hence the of heat transferred to the river Is $Q_{2} -W = (100 -59.47=40.53$

6 0

3 years ago

How many atoms of hydrogen are there in 18g of water ?

Bingel [31]

Answer:

They are 1.204×10^24 atoms of hydrogen present in 18 grams of water. In order to calculate this,it is necessary to compute the number of hydrogen moles present in the sample.

6 0

2 years ago

Dioxane, C4H8O2, has an enthalpy of fusion of 145.8 J g–1 and its melting point temperature is 11.0 °C. How much heat is require

kumpel [21]

Answer:

20703.6J

Explanation:

Quantity of heat (Q) = mass of dioxane × enthalpy of fusion

Mass of dioxane = 142g

Enthalpy of fusion of dioxane = 145.8J/g

Q = 142g × 145.8J/g = 20703.6J

5 0

3 years ago

Develop a model to show the chemical potential energy of wood and how that energy is transformed.

Phantasy [73]

Answer:

Explanation:

Chemical potential energy is the chemical energy stored (or property) of a substance. One chemical potential energy of wood is combustion. Combustion involves the burning of a substance in excess oxygen (in this case open air). <u>The chemical energy stored here is transformed to thermal/heat energy after combustion due to the large amount of heat evolved/produced</u>.

NOTE:

The model above also that combustion is an exothermic reaction because it involves the release of heat into it's surrounding.

6 0

3 years ago