Answer:
A. They contain older stars and less gas and dust.
Explanation:
There are three types of galaxies:
Elliptical galaxies are galaxies shaped like an ellipse, while spiral galaxies consist of a flat, rotating disk that contains stars, gas, and dust, and a central concentration of stars called the bulge.
The difference between elliptical and spiral galaxies is in the amount of gas and dust they contain. Spiral galaxies contain large amounts of gas and dust, which means that new stars are born very often. This makes them brighter than relatively dim elliptical galaxies, which contain less gas and dust. This is why fewer new and brighter stars are born in elliptical galaxies, leaving them with older, dimmer stars.
b. cacao
c. mangoes
d. coffee
correct answer is D COFFEE
correct answer is D COFFEE
correct answer is D COFFEE
The balanced chemical equation for the combustion of octane is 2 C8H18 + 25 O2 → 16 CO2 + 18 H2O. From the stoichiometry of the reaction, 3.50 mol of CO2 will need approximately 50g of octane.
The combustion of octane (C8H18) in the presence of oxygen (O2) produces carbon dioxide (CO2) and water (H2O). The balanced chemical equation for this reaction is: 2 C8H18 + 25 O2 → 16 CO2 + 18 H2O.
To calculate the mass of octane needed to release 3.50 mol CO2, we need to understand the stoichiometry of the reaction. From the balanced equation, we can see that 16 mol of CO2 is produced from 2 mol of C8H18. So, 1 mol of C8H18 produces 8 mol of CO2.
Therefore, to produce 3.50 mol of CO2, we would need 3.50/8 = 0.4375 mol of C8H18. The molar mass of octane is approximately 114 g/mol, so the required mass would be 0.4375mol x 114g/mol = approximately 50g.
#SPJ12
The combustion of octane produces carbon dioxide and water, as described by the balanced chemical equation C8H18 + 12.5O2 → 8CO2 + 9H2O. To produce 3.50 mol of CO2, approximately 50g of octane is needed.
The combustion of octane (C8H18) in the presence of oxygen (O2) produces carbon dioxide (CO2) and water (H2O). The balanced chemical equation for this reaction is: C8H18 + 12.5O2 → 8CO2 + 9H2O.
Considering the stoichiometry of the reaction, we can see that 1 mol of octane produces 8 moles of CO2. Therefore, to produce 3.50 mol of CO2, the amount of octane required would be 3.50/8 = 0.4375 mol. Converting this to mass using the molar mass of octane (114.22 g/mol), we get 0.4375 mol * 114.22 g/mol ≈ 50 g. Thus, approximately 50g of octane is needed to produce 3.50 mol of CO2.
#SPJ6
(2) increases
(3) remains the same
Answer: option (1) decreases.
Explanation:
May be you have experienced that: when you go to the beach, where the atmposhpere pressure is greater than the atmosphere pressure in places that are at higher altitudes, the water takes longer to boil. That is because the boiling temperature is greater, and you need more total heat (more time) to permit the liquid to reach that temperature.
The reason why that happens is because substances boil when the vapor pressure (the pressure of the particles of vapor over the liquid) equals the atmosphere pressure. So, when the atmposhere pressure increases, the temperature at which the vapor pressure reaches the atmosphere pressure also increases, and when the atmosphere pressure decreases, the temperature at which the vapor pressure reaches the atmosphere pressure decreases.
b. 35 g
c. 65 g
d. 6.02 × 1023 g
Answer: physical change
Explanation:
A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these changes
Example: Melting of ice
A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these changes.
Example: Corrosion of iron called as rusting.
Thus when the metal wire in an incandescent light bulb glows when the light is switched on and stops flowing when it is switched off is just a physical change as there is no change in chemical composition.