Answer : The specific heat of substance is ![0.235J/g^oC](https://tex.z-dn.net/?f=0.235J%2Fg%5EoC)
Explanation :
Formula used :
![Q=m\times c\times \Delta T](https://tex.z-dn.net/?f=Q%3Dm%5Ctimes%20c%5Ctimes%20%5CDelta%20T)
or,
![Q=m\times c\times (T_2-T_1)](https://tex.z-dn.net/?f=Q%3Dm%5Ctimes%20c%5Ctimes%20%28T_2-T_1%29)
where,
Q = heat needed = 4.90 kJ = 4900 J
m = mass of sample = 894.0 g
c = specific heat of substance = ?
= initial temperature = ![-5.8^oC](https://tex.z-dn.net/?f=-5.8%5EoC)
= final temperature = ![17.5^oC](https://tex.z-dn.net/?f=17.5%5EoC)
Now put all the given value in the above formula, we get:
![4900J=894.0g\times c\times [17.5-(-5.8)]^oC](https://tex.z-dn.net/?f=4900J%3D894.0g%5Ctimes%20c%5Ctimes%20%5B17.5-%28-5.8%29%5D%5EoC)
![c=0.235J/g^oC](https://tex.z-dn.net/?f=c%3D0.235J%2Fg%5EoC)
Therefore, the specific heat of substance is ![0.235J/g^oC](https://tex.z-dn.net/?f=0.235J%2Fg%5EoC)
Answer: Most of the hormones released by endocrine system are regulated by negative feedback mechanism.
- Negative feedback mechanism functions to reduce the intensity of original stimulus in order to maintain homeostasis.
Explanation:
When blood calcium levels are decreased, parathyroid gland releases parathyroid hormone (PTH).
PTH acts on bone and stimulate bone resorption by promoting osteoclastic activity. It stimulates reabsorption of calcium in kidneys. PTH promotes calcitriol synthesis that acts on small intestine to increase calcium absorption.
Action of PTH increases blood calcium levels.
When blood calcium levels are increased, thyroid gland releases hormone calcitonin.
Calcitonin opposes PTH and acts to deposit calcium in the bone.
Calcitonin acts on osteoblasts and promote increase in bone mass.
Action of calcitonin decreases blood calcium levels.
I believe it would actually be a C. Solution as the contents needed to make coffee are well mixed and have been fully dissolved in the solvent.
Answer:
Their positive charge is located in the small nucleus
Explanation:
Ernest Rutherford performed the gold foil experiment in 1911 where he used alpha particles generated from a radioactive source to bombard a thin gold foil.
In his experiment, he observed that the bulk of the alpha particles passed through the gold foil, just a tiny fraction was deflected back. To explain his findings, Rutherford proposed that an atom is made of positively charged centre where nearly all the mass is concentrated called nucleus. Surrounding the nucleus is a large space containing electrons.
C. Solid
The particles in a solid are held together by strong attractive forces so they can't move freely. However in gases and liquids the attractive force is weaker to they can move more easily.