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2 years ago

When did the mass extinctions happen

1 answer:

4 0

Out of the five major mass extinction, one is Cretaceous-Tertiary extinction (K-T extinction). It happened 66 million years ago marked by the end of the Cretinous period.

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Which statement BEST describes why licensed health care workers are held to a higher standard?

strojnjashka [21]

Answer:

They agree to ethical standards when they are licensed.

Explanation:

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3 years ago

Does anybody know the answer if so explain

a_sh-v [17]

Answer:

synthesis

Explanation:

I believe answer is d a synthesis reaction

5 0

2 years ago

n a coffee cup calorimeter, 100.0 mL of 1.0M NaOH and 100.0 mL of 1.0M HCl are mixed. Both solutions were originally at 24.6 deg

RoseWind [281]

Answer:

Explanation:

mass of the solution = volume x density = 200 x 1 = 200 gm

heat absorbed = m x s x Δ t , s is specific heat , Δt is rise in temperature

= 200 x 4.18 x ( 31.3 - 24.6 )

= 5601 J .

This is the enthalpy change required.

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3 years ago

Three principal models of isostasy are used: 1. The Airy–Heiskanen model – where different topographic heights are accommodated

miss Akunina [59]

Answer:

the answer is B

Explanation:

8 0

2 years ago

0. A liquid solution of LiCl in water at 25°C contains 1 mol of LiCl and 7 mol of water. If 1 mol of LiCl⋅3H2O(s) is dissolved i

kupik [55]

Answer:

19.488 kJ

Explanation:

The overall reaction mechanism shows the reaction between LiCl and H₂O

$LiCl.3H_2O ------> Li +\frac{1}{2} Cl_2+3H_2+\frac{3}{2} O_2$ -------- (1)

$2Li+Cl_2+10H_2O ----->LiCl.10H_2O$ -------- (2)

$3H_2+\frac{3}{2}O_2 -----> 3H_2O$ --------- (3)

$LiCl.7H_2O ------> Li + \frac{1}{2} Cl_2+7H_20$ ---------- (4)

The overall reaction =

$LiCl.7H_2O +LiCl.3H_2O ------> 2LiCl.10H_2O$

The heat effects of the above reactions from 1-4 respectively are in the order ; 11311.34 kJ, -857.49 kJ, -873.61 kJ and 439.288kJ respectively

The overall enthalpy change is:

$\delta H = \delta H _{LiCl.3H_2O}+\delta H_{3H_2O} + \delta H_{2(LiCl.5H_2O)} + \delta H _{liCl.7H_2O}$

$\delta H =Q$ at constant pressure;

Thus; Q = 1311.3 (kJ) 857.49 (kJ) -873.61 (kJ) + 439.288 (kJ)

Q = 19.488 kJ

Thus, the heat effect = 19.488 kJ after the addition of 1 mol of LiCl⋅3H2O(s)

4 0

3 years ago