Answer:- Density is 2.54 gram per mL.
Solution:- 
Mass of the marble ball is given as 9.513 g and it's volume is 3.75 mL.
To calculate the density of the marble ball let's plug in the values in the formula:


So, the density of the marble ball is 2.54 gram per mL.
The number of mole of lithium, Li needed for the reaction is 3.2 moles (Option D)
<h3>Balanced equation </h3>
4Li + N₂(g) → 2Li₂N
From the balanced equation above,
2 moles of Li₂N were obtained from 4 moles of Li
<h3>How to determine the mole of lithium needed </h3>
From the balanced equation above,
2 moles of Li₂N were obtained from 4 moles of Li
Therefore,
1.6 moles of Li₂N will be obtained from = (1.6 × 4) / 2 = 3.2 moles of Li
Thus, 3.2 moles of Li are needed for the reaction
Learn more about stoichiometry:
brainly.com/question/14735801
Answer:
B.) 36.0 grams
Explanation:
To find the mass of water, you need to (1) convert grams H₂ to moles (using the molar mass), then (2) convert moles H₂ to moles H₂O (using mole-to-mole ratio from reaction coefficients), and then (3) convert moles H₂O to grams (using the molar mass). It is important to arrange the conversions in a way that allows for the cancellation of units.
Molar Mass (H₂): 2(1.008 g/mol)
Molar Mass (H₂): 2.016 g/mol
Molar Mass (H₂O): 2(1.008 g/mol) + 15.998 g/mol
Molar Mass (H₂O): 18.014 g/mol
2 H₂ + O₂ -----> 2 H₂O
^ ^
4.0 g H₂ 1 mole 2 moles H₂O 18.014 g
--------------- x ---------------- x ------------------------ x --------------- = 36 g H₂O
2.016 g 2 moles H₂ 1 mole
Answer:
Have high melting points and high boiling points.
Explanation:
- Covalent bonds are types of chemical bonds that result from the sharing of electrons between non-metal atoms.
- Covalent bonds result in the formation of covalent compounds.
- Covalent compounds are characterized by low melting and boiling points.
- Therefore, it won't be true to say they have high melting and boiling points.
- Other properties of covalent bonds include poor conductors of electricity and heat, gases or liquids at room temperature, and are non-polar compounds among others.
The correct answer is option C, that is, hypothesis.
The hypothesis is the starting building block in the scientific method. It is also illustrated as an educated guess, based on previous observation and knowledge. A hypothesis refers to a recommended solution for an unexplained event, which does not fit into the present accepted scientific theory.
The fundamental concept of a hypothesis is that there is no pre-determined result. For a hypothesis to be considered as scientific hypothesis, it has to be something, which can be refuted or supported via carefully crafted observation or experimentation.