What is always true of a weak acid

What is a flame,metion two types of flames

12345 [234]

Answer:

A flame is defined as the gaseous part of the fire which is visible to us. A flame is created due to the high exothermic reaction.

Two types of flames based on the amount of oxygen available are:

Non-luminous or blue flame: In this type of flame the amount of oxygen is sufficiently large and it gives blue flame. For example: flame of Gas stove.
Luminous flame: In this type of flame, the oxygen availability id not sufficient for the complete combustion and left unburnt carbon particles that forms yellow light flame. For example: kerosene lamp.

7 0

3 years ago

A substance undergoes a change. Which of the following indicates that the change

LekaFEV [45]

Answer:

change of color

Explanation:

when a substance undergoes a change of color it is an indication that it was chemical

5 0

3 years ago

Natural gas burns in air to form carbon dioxide and water, releasing heat. CH4(g)+2O2(g)→CO2(g)+2H2O(g) ΔHrxn = -802.3 kJ.

Olenka [21]

Answer:

1) Minimum mass of methane required to heat 45.0 g of water by 21.0°C is 0.0788 g.

2) Minimum mass of methane required to heat 50.0 g of water by 26.0°C is 0.108 g.

Explanation:

$CH_4(g)+2O_2(g)\rightarrow CO_2(g)+2H_2O(g) ,\Delta H_{rxn} =-802.3 kJ$

1) Minimum mass of methane required to raise the temperature of water by 21.0°C.

Mass of water = m = 45.0 g

Specific heat capacity of water = c = 4.18 J/g°C

Change in temperature of water = ΔT = 21.0°C.

Heat required to raise the temperature of water by 21.0°C = Q

$Q=mc\Delta T= 45.0 g\times 4.18 J/g^oC\times 21.0^oC$

Q = 3,950.1 J = 3.9501 kJ

According to reaction 1 mole of methane on combustion gives 802.3 kJ of heat.

Then 3.950.1 kJ of heat will be given by:

$=\frac{3.950.1 kJ}{802.3 kJ}=0.004923 mol$

Mass of 0.004923 moles of methane :

0.004923 mol × 16 g/mol=0.0788 g

Minimum mass of methane required to heat 45.0 g of water by 21.0°C is 0.0788 g.

2) Minimum mass of methane required to raise the temperature of water by 26.0°C.

Mass of water = m = 50.0 g

Specific heat capacity of water = c = 4.18 J/g°C

Change in temperature of water = ΔT = 26.0°C.

Heat required to raise the temperature of water by 21.0°C = Q

$Q=mc\Delta T= 50.0 g\times 4.18 J/g^oC\times 26.0^oC$

Q = 5,434 J= 5.434 kJ

According to reaction 1 mole of methane on combustion gives 802.3 kJ of heat.

Then 5.434 kJ of heat will be given by:

$=\frac{5.434 kJ}{802.3 kJ}=0.006773 mol$

Mass of 0.006773 moles of methane :

0.006773 mol × 16 g/mol= 0.108 g

Minimum mass of methane required to heat 50.0 g of water by 26.0°C is 0.108 g.

6 0

4 years ago

Which element would have a full outer shell of electrons if it gained three electrons?

Vsevolod [243]

Answer:

Octet Rule is defined as the chemical rule in which atoms tend to form bonds in such a way that it completes its valence shell or tend to achieve the configuration of a noble gas.

Explanation:

The lithium is chemical element, which has atomic number 3. It has one valence electron in its outermost shell, therefore, it will require 7 more electrons to complete its octet.

The element nitrogen has the atomic number 7, such that it has 5 valence electrons in its outer most shell. Therefore, it will require 3 more electrons to complete its octet.

The noble gas Argon have complete octet, such that it does not require any electrons to complete its octet. the gas is inert and non-reactive.

The chemical element Boron has atomic number 5, such that it has three electrons in its outer most shell. Therefore, it will require 5 more electrons to complete its octet.

Hence, the correct option is Nitrogen.

5 0

3 years ago

Read 2 more answers

What is the orientation of the two unhybridized p orbitals on Be with respect to the two Be−F bonds?

Len [333]

Answer:

b) Both p orbitals are perpendicular to the F−Be−F bond axes.

Explanation:

Be has 2 electrons in its valence shell, subshell s is fulfilled, so it has no unpaired electrons in its ground state to make bonds with F. So, it can promote the electrons to the 2p orbital and will having sp hybridization.

The bond between the orbitals sp and the p orbital of F are in opposite directions but the same ax. The two bonds are equivalent, and the molecule had a linear geometry. The two unhybridized p orbitals on Be are vacant, and so they are perpendicular to the F-Be-F bond axes.

7 0

4 years ago