Answer:
the direction of the object
Explanation:
Electronegativity of boron is the highest in the group and it will form covalent bonds in all his combinations.
The rest of the group will form bonds with intermediate nature between covalent and ions bods in their respective compounds, with thallium (Tl) behaving most close to a metal.
Moreover boron have a very high melting points (around 2200 °C) while in the boron cristal the chemical bonds are directed in space, similar with carbon suggesting his nature as a non-metal.
Other elements form the group Al, Ga, In, Tl have lower melting points 660, 30, 157 and 304 °C, respectively. Also in the elemental state, they have metallic characteristics: metalic luster, ductility, high electrical and thermal conductivity.
Answer:
C. Gas exchange occurs through the placenta.
Explanation:
The fetus is a developing baby in the womb or uterus. The fetus is incapable of performing certain life processes itself and hence, depends on the mother to do them. One of these processes is GAS EXCHANGE. Gas exchange occurs in the fetus via a structure called PLACENTA.
Placenta is a structure that forms in the uterus during pregnancy. It helps the developing fetus supply oxygen and nutrients from the mother and also remove wastes from the fetus back to the mother. The oxygen is taken into the fetus via the PLACENTA while the carbon dioxide (waste product of respiration) is removed via the PLACENTA. Hence, Gas exchange occurs through the placenta.
Answer: E. It decreases the value of Eact.
Explanation:
Activation energy is the extra energy that must be supplied to reactants in order to cross the energy barrier and thus convert to products.
A catalyst is a substance which increases the rate of a reaction by taking the reaction through a different path which involves lower activation energy and thus more molecules can cross the energy barrier and more molecules convert to products.
The catalyst itself does not take part in the chemical reaction and is regenerated as such at the end.