What part of the atom is represented by the letter Z?

In a titration, the point at which one drop of base turns the acid indicator a pink color that lasts for 30 seconds is called th

xxTIMURxx [149]

The point at which one drop of base turns the acid indicator into a pink color that lasts for thirty seconds in doing titration is called the end point or the equivalence point.

End point or the equivalence point is the one responsible for the pink color that lasts for thirty seconds.

8 0

3 years ago

What is the Definition of "Folded Mountain" in science terms?

just olya [345]

Fold mountains are mountains that form mainly by the effects of folding on layers within the upper part of the Earth's crust. Before either plate tectonic theory developed, or the internal architecture of thrust belts became well understood, the term was used for mostmountain belts, such as the Himalayas.

3 0

3 years ago

A sample of nitrogen gas is stored in a 489.6 mL flask at 108 kPa and 10.0°C. The gas is transferred to a 750.0 mL flask at 28.7

Wewaii [24]

Answer:

P2= 125.26 Kpa

Explanation:

V1= 489.6 ml=0.4896L

V2= 750 ml= 0.750L

V1= 180 KPa= 180000 Pa

P2= ?

T1= 10 = 10 + 273.15 = 283.15K

T2= 28.7+273.15= 301.85K

180000Pa* 0.4896L/ 283.15K * 301.85K/0.75L

P2= 12526.28553

P2= 125.26 KPa

5 0

3 years ago

A 5.000 g sample of Niso4 H2O decomposed to give 2.755 g of anhydrous NiSO4.

Vinvika [58]

Answer:

a) 7.0.

b) Nickel sulfate hepta hydrate.

c) 280.83 g/mol.

d) 44.9%.

Explanation:

a) What is the formula of the hydrate?

The mass of the hydrated sample (NiSO₄.xH₂O) = 5.0 g,

The mass of the anhydrous salt (NiSO₄) = 2.755 g,

The mass of water = 5.0 g - 2.755 g = 2.245 g.

∴ no. of moles of water = mass/molar mass = (2.245 g)/(18.0 g/mol) = 0.1247 mol.

∴ no. of moles of anhydrous salt (NiSO₄) = mass/molar mass = (2.755 g)/(154.75 g/mol) = 0.0178 mol.

∴ water of crystallization in the sample (x) = no. of moles of water/no. of moles of anhydrous salt (NiSO₄) = (0.1247 mol)/(0.0178 mol) = 7.0.

b) What is the full chemical name for the hydrate?

The name of the salt (NiSO₄.7H₂O) is Nickel sulfate hepta hydrate.

c) What is the molar mass of the hydrate?

(NiSO₄.7H₂O)

The molar mass = molar mass of NiSO₄ + 7(molar mass of H₂O) = (154.75 g/mol) + 7(18.0 g/mol) = 280.83 g/mol.

d) What is the mass % of water in the hydrate?

The mass % of water = (mass of water)/(mass of hydrated sample) x 100 = (2.245 g)/(5.0 g) x 100 = 44.9%.

8 0

3 years ago

Given the equation C3H8(g) + O2(g) = CO2(g) + H2O(g) and that the enthalpies of formation for H2O(g) = -241.8 kJ/mol, CO2(g) = -

kari74 [83]

Answer: 72.4 kJ/mol

Explanation:

The balanced chemical reaction is,

$C_3H_8(g)+5O_2(g)\rightarrow 3CO_2(g)+4H_2O(l)$ $\Delta H=-2220.1kJ/mol$

The expression for enthalpy change is,

$\Delta H=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)]$

$\Delta H=[(n_{CO_2}\times \Delta H_{CO_2})+(n_{H_2O}\times \Delta H_{H_2O})]-[(n_{O_2}\times \Delta H_{O_2})+(n_{C_3H_8}\times \Delta H_{C_3H_8})]$

where,

n = number of moles

$\Delta H_{O_2}=0$ (as heat of formation of substances in their standard state is zero

Now put all the given values in this expression, we get

$-2220.1=[(3\times -393.5)+(4\times -241.8)]-[(5\times 0)+(1\times \Delta H_{C_3H_8})]$

$\Delta H_{C_3H_8}=72.4kJ/mol$

Therefore, the heat of formation of propane is 72.4 kJ/mol

7 0

3 years ago