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3 years ago

Which statement best reflects a change in climate?

Chemistry

1 answer:

zalisa [80]3 years ago

6 0

Answer:

droughts in California have become more common in California

Explanation:

Climate is weather over time which means that the first and the third one are just isolated incidents and the last answer choice shows climate but it doesn't show a change in climate

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If the roller coaster car in the above problem were moving with twice the speed (4m/s), then what would be its

OleMash [197]

Explanation:

New kinetic energy= ½mv'²

v' =4m/s

m= 2000kg

KE = ½ (2000) (4)²

=16000 Joules

3 0

3 years ago

cylinder contains 250 g of Helium at 200 K. The external pressure is constant at 1 atm. The temperature of the surroundings is l

brilliants [131]

Answer:

The system gains 126100 J

Explanation:

The heat can be calculated by the equation:

Q = nxCxΔT, where Q is the heat, C is the heat capacity,n is the number of moles and ΔT is the variation of temperature (final - initial). The number of moles is the mass divided by the molar mass, so:

n = 250/4 = 62.5 mol.

The system must be in thermal equilibrium with the surroundings, so if the temperature of the surroundings decreased 97 K, the temperature of the system increased by 97 K, so ΔT = 97 K

Q = 62.5x20.8x97

Q = 126100 J

6 0

4 years ago

Determine the heat of reaction for the process TiO2(s) + 4HCl(g) TiCl4(l) + 2H2(g) + O2(g) using the information given below: Ti

Aleks [24]

Answer : The heat of reaction for the process is, 1374.7 kJ

Explanation :

According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.

According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.

The main chemical reaction is,

$TiO_2(s)+4HCl(g)\rightarrow TiCl_4(l)+2H_2(g)+O_2(g)$ $\Delta H_{rxn}=?$

The intermediate balanced chemical reaction will be,

(1) $Ti(s)+O_2(g)\rightarrow TiO_2(s)$ $\Delta H_1=-939.7kJ$

(2) $2HCl(g)\rightarrow H_2(g)+Cl_2(g)$ $\Delta H_2=-184.6kJ$

(3) $Ti(s)+2Cl_2(g)\rightarrow TiCl_4(l)$ $\Delta H_3=-804.2kJ$

We reversing reaction 1, 3 and multiplying reaction 2 by 2 and then adding all the equations, we get :

(1) $TiO_2(s)\rightarrow Ti(s)+O_2(g)$ $\Delta H_1=939.7kJ$

(2) $4HCl(g)\rightarrow 2H_2(g)+2Cl_2(g)$ $\Delta H_2=2\times (-184.6kJ)=-369.2kJ$

(3) $TiCl_4(l)\rightarrow Ti(s)+2Cl_2(g)$ $\Delta H_3=804.2kJ$

The expression for heat of reaction for the process is:

$\Delta H_{rxn}=\Delta H_1+\Delta H_2+\Delta H_3$

$\Delta H_{rxn}=(939.7kJ)+(-369.2kJ)+(804.2kJ)$

$\Delta H_{rxn}=1374.7kJ$

Therefore, the heat of reaction for the process is, 1374.7 kJ

3 0

3 years ago

Find the mass in 6.2 moles of lithium bromide

Art [367]

1
mol of lithium bromide has a mass of
86.85

g
⋅
m
o
l
−
1
. You have
2.6
moles of the stuff.
Explanation:
So mass
=

86.85

g
⋅
m
o
l
−
1
×

2.6

m
o
l

=

?
?

g
.

7 0

4 years ago

Need to lose one electron to form a stable octet

tamaranim1 [39]

Alkali metals need to lose 1 electron to form a stable octet.

8 0

3 years ago

Read 2 more answers