Can you help me please, I’ll mark brainliest.

2) If 100.0 J of heat are added to 20.0 g of water at 30.0°C, what will be the final

anzhelika [568]

The final temperature of the water will be 31.2 °C... i don’t know the second one sorry :(

3 0

2 years ago

Can someone help me? It needs to have a diagram that has arrows.

daser333 [38]

Answer: The enthalpy change for formation of butane is -125 kJ/mol

Explanation:

The balanced chemical reaction is,

$C_4H_{10}(g)+\frac{13}{2}O_2(g)\rightarrow 4CO_2(g)+5H_2O(l)$

The expression for enthalpy change is,

$\Delta H=[n\times H_f{products}]-[n\times H_f{reactants}]$

Putting the values we get :

$\Delta H=[4\times H_f_{CO_2}+5\times H_f_{H_2O}]-[1\times H_f_{C_4H_{10}}+\frac{13}{2}\times H_f_{O_2}]$

$-2877=[(4\times -393)+(5\times -286)]-[1\times H_f_{C_4H_{10}}+\frac{13}{2}\times 0]$

$H_f_{C_4H_{10}=-125kJ/mol$

Thus enthalpy change for formation of butane is -125 kJ/mol

5 0

3 years ago

Fe2O3 + 2Al -> Al2O3 + 2Fe

pashok25 [27]

Fe2O3 + 2Al ---> Al2O3 + 2Fe
Mole ratio Fe2O3 : Al = 1:2
No. of moles of Fe2O3 = Mass/RMM = 250 / (55.8 * 2 + 16 * 3) = 1.56641604 moles
No. of moles of Al = 150/27 = 5.555555555 moles.
Mole ratio 1 : 2. 1.56641604 * 2 = 3.13283208 moles of Al, but you have 5.555555555 moles of Al. So Al is in excess. All of it won't react.

So take the Fe2O3 and Fe ratio to calculate the mass of iron metal that can be prepared.
RMM of Fe2O3 / Mass of Fe2O3 = RMM of 2Fe / Mass of Fe 159.6 / 250 = 111.6 / x x = 174.8 g of Fe

7 0

3 years ago

Read 2 more answers

Which isotope will spontaneously decay and emit particles with a charge of +2?

VikaD [51]

Answer: The correct option is 4.

Explanation: All the options will undergo some type of radioactive decay processes. There are 3 decay processes:

1) Alpha decay: It is a decay process in which alpha particle is released which has has a mass number of 4 and a charge of +2.

$_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}\textrm{Y}+_2^4\alpha$

2) Beta-minus decay: It is a decay in which a beta particle is released. The beta particle released has a mass number of 0 and a charge of (-1).

$_Z^A\textrm{X}\rightarrow _{Z+1}^A\textrm{Y}+_{-1}^0\beta$

3) Beta-plus decay: It is a decay process in which a positron is released. The positron released has a mass number of 0 and has a charge of +1.

$_Z^A\textrm{X}\rightarrow _{Z-1}^A\textrm{Y}+_{+1}^0\beta$

For the given options:

Option 1: This nuclei will undergo beta-plus decay process to form $_{25}^{53}\textrm{Mn}$

$_{26}^{53}\textrm{Fe}\rightarrow _{25}^{53}\textrm{Mn}+_{+1}^0\beta$

Option 2: This nuclei will undergo beta-minus decay process to form $_{80}^{198}\textrm{Hg}$

$_{79}^{198}\textrm{Au}\rightarrow _{80}^{198}\textrm{Hg}+_{-1}^0\beta$

Option 3: This nuclei will undergo a beta minus decay process to form $_{56}^{137}\textrm{Ba}$

$_{55}^{137}\textrm{Cs}\rightarrow _{56}^{137}\textrm{Ba}+_{-1}^0\beta$

Option 4: This nuclei will undergo an alpha decay process to form $_{85}^{216}\textrm{At}$

$_{87}^{220}\textrm{Fr}\rightarrow _{85}^{216}\textrm{At}+_2^4\alpha$

Hence, the correct option is 4.

7 0

3 years ago

Read 2 more answers

What is the volume of 220 grams of an object with a density of 55g/cm square

AnnyKZ [126]

I'm assuming that you meant 55 g/cm^3. Density= $\frac{Mass}{Volume}$ . This is the definition of density. If you rearrange this equation by multiplying each side of the equation by the volume, you get: (Density)(Volume)=Mass. Divide each side by the density to get: Volume=Mass/Density. Now just plug everything in:
V=220 (grams)/55 (grams/cm^3)=<u>4 cm^3</u>

4 0

3 years ago