True or False? You should change the subscripts to balance chemical equations.

Diatomic O2 can react with the element magnesium to form magnesium oxide (MgO). The balanced chemical equation is: 2Mg + O2 → 2M

tigry1 [53]

Answer:

We will expect 4 moles of MgO to be formed (option b).

Explanation:

Step 1: The balanced equation

2Mg + O2 → 2MgO

Step 2: Data given

Number of moles of Magnesium = 4 moles

Oxygen = in excess → this means Magnesium is the limiting reactant

Magnesium will completely be consumed ( 4 moles). There will remain 0 moles.

For 2 moles of magnesium consumed, we need 1 mole of oxygen to produce 2 moles of MgO.

For 4 moles of magnesium, we need 4/2 = 2 moles of oxygen.

For 4 moles of magnesium, we will produce 4/1 = 4 moles of MgO

We will expect 4 moles of MgO to be formed (option b).

4 0

3 years ago

I need help please, thanks!

oee [108]

Answer:

This question is somehow not clear, because a typical human eye can notice objects which have wavelengths from about 380 to 740 nanometers. This is called visible spectrum (the portion of the electromagnetic spectrum that is visible to the human eye). Electromagnetic radiation in this range of wavelengths is called visible light or simply light.

Someone even can see extra colors - they able to see beyond the visible spectrum. The reason that the human eye can see the spectrum is because those specific wavelengths stimulate the retina in the human eye. The human retina can only detect incident light that falls in waves from about 380 to 740 nanometers long, so we can’t see microwave or ultraviolet wavelengths. This also applies to infrared lights which has wavelengths longer than visible and shorter than microwaves, thus being invisible to the human eye.

In conclusion, the human eye can not notice that objects with wavelength not in the range of 380 to 740 nanometers.

Explanation:

5 0

2 years ago

The products of photosynthesis are the starting materials of cellular respiration true or false

notsponge [240]

True....

Explanation

Cells use oxygen to release energy during photosynthesis/chlorophyll/cellular respiration. For photosynthesis, the starting materials are water and carbon dioxide, and the products are sugar and oxygen. For cellular respiration, the starting materials are oxygen and sugar, and the products are carbon dioxide and water.

4 0

2 years ago

Flourine is found to undergo 10% radioactivity decay in 366 minutes determine its halflife

yuradex [85]

Answer:

$\boxed{\text{2408 min}}$

Explanation:

The integrated rate law for radioactive decay is

$\ln\dfrac{N_{0}}{N_{t}} = kt$

1. Calculate the decay constant

$\begin{array}{rcl}\ln \dfrac{100}{90} & = & k \times 366\\\\1.054 & = & 366k\\\\k & = & \dfrac{1.054 }{366}\\\\k & = & 2.879 \times 10^{-4} \text{ min}^{-1}\\\end{array}\\\\$

2. Calculate the half-life

$t_{\frac{1}{2}} = \dfrac{\ln2}{k}\\\\t_{\frac{1}{2}} = \dfrac{\ln2}{2.879 \times 10^{-4} \text{ min}^{-1}} = \text{2408 min}\\\\\text{The half-life for decay is } \boxed{\textbf{2408 min}}$

8 0

3 years ago

The molarity of an aqueous sodium phosphate solution is 0.650 M. What is the molality of sodium ions present in this solution? T

netineya [11]

Answer:

molality of sodium ions is 1.473 m

Explanation:

Molarity is moles of solute per litre of solution

Molality is moles of solute per kg of solvent.

The volume of solution = 1 L

The mass of solution = volume X density = 1000mL X 1.43 = 1430 grams

The mass of solute = moles X molar mass of sodium phosphate = 0.65X164

mass of solute = 106.6 grams

the mass of solvent = 1430 - 106.6 = 1323.4 grams = 1.3234 Kg

the molality = $\frac{moles of solute}{mass of solvent in kg}=\frac{0.65}{1.323}= 0.491m$

Thus molality of sodium phosphate is 0.491 m

Each sodium phosphate of molecule will give three sodium ions.

Thus molality of sodium ions = 3 X 0.491 = 1.473 m

7 0

3 years ago