Ask question

Ask question

All categories

2 years ago

15

An alien civilization has different names and symbols for six elements. Place each element in the correct location in the period

ic table.

2 answers:

olga2289 [7]2 years ago

5 0

Answer:

The picture

Explanation:

You just have to count the number of valence electrons and place the unknown elements on the periodic table according to their atomic number.

Margarita [4]2 years ago

3 0

Answer:

why whould I know that!!??

Explanation:

You might be interested in

Lithium-6 has a mass of 6.0151 amu and lithium-7 has a mass of 7.0160 amu. The relative abundance of Li-6 is 7.42% and the relat

horsena [70]

Average atomic mass is the weighted average atomic masses with regard to the relative abundance of the isotopes
average atomic mass of Li = relative abundance of Li-6 x mass of Li-6 + relative abundance of Li-7 x mass of Li-7
average atomic mass of Li = (7.42% x 6.0151 a.m.u) + (92.58% x 7.0160 a.m.u)
= 0.446 + 6.495
= 6.941 amu
average atomic mass of Li is 6.941 amu

3 0

2 years ago

Read 2 more answers

You're provided a 0.50 M solution of HCl. How many moles of HCl are present in 25 ml of this solution?

ddd [48]

Answer:

0.0125 moles of HCl

Explanation:

(0.50 mol/L)(0.025 L) = 0.0125 moles of HCl

4 0

2 years ago

How many moles of NH3 can be produced from 12.0 mol of H2 and excess N2? Express your answer numerically in moles. View Availabl

VladimirAG [237]

Answer:

A) 8.00 mol NH₃

B) 137 g NH₃

C) 2.30 g H₂

D) 1.53 x 10²⁰ molecules NH₃

Explanation:

Let us consider the balanced equation:

N₂(g) + 3 H₂(g) ⇄ 2 NH₃(g)

Part A

3 moles of H₂ form 2 moles of NH₃. So, for 12.0 moles of H₂:

$12.0molH_{2}.\frac{2molNH_{3}}{3molH_{2}} =8.00molNH_{3}$

Part B:

1 mole of N₂ forms 2 moles of NH₃. And each mole of NH₃ has a mass of 17.0 g (molar mass). So, for 4.04 moles of N₂:

$4.04molN_{2}.\frac{2molNH_{3}}{1molN_{2}} .\frac{17.0gNH_{3}}{1molNH_{3}} =137gNH_{3}$

Part C:

According to the <em>balanced equation</em> 6.00 g of H₂ form 34.0 g of NH₃. So, for 13.02g of NH₃:

$13.02gNH_{3}.\frac{6.00gH_{2}}{34.0gNH_{3}} =2.30gH_{2}$

Part D:

6.00 g of H₂ form 2 moles of NH₃. An each mole of NH₃ has 6.02 x 10²³ molecules of NH₃ (Avogadro number). So, for 7.62×10⁻⁴ g of H₂:

$7.62 \times 10^{-4} gH_{2}.\frac{2molNH_{3}}{6.00gH_{2}} .\frac{6.02\times 10^{23}moleculesNH_{3} }{1molNH_{3}}=1.53\times10^{20}moleculesNH_{3}$

3 0

3 years ago

A sample of methane gas has a volume of 10 l at a pressure of 1.5 atm and a temperature of 20 °c. what volume does the gas occup

a_sh-v [17]

We can use combined gas laws to solve for the volume of the gas
$\frac{PV}{T}$
where P - pressure, V - volume , T - temperature and k - constant
$\frac{P1V1}{T1} = \frac{P2V2}{T2}$
parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
T1 - temperature in Kelvin - 20 °C + 273 = 293 K
T2 - 40 °C + 273 = 313 K
substituting the values
$\frac{1.5 atm*10L}{293 K} = \frac{0.9 atm*V}{313K}$
V = 17.8 L
volume of the gas is 17.8 L

7 0

2 years ago

Which organism has a central brain A.sponge B. hydra C. flatworm D. fish

Scilla [17]

D. Fish
The brain is part of an organism's central nervous system. Simpler organisms such as sponges, hydrae, and flatworms lack the complexity in their central nervous systems to have a brain. A fish, on the other hand, is complex enough to have a central brain.

8 0

2 years ago

Read 2 more answers