Answer:
0.81 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\ [/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{4.9 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{4.9}{6.02} \\ = 0.813953...[/tex]
We have the final answer as
0.81 molesHope this helps you
Plzz help me well mark brainliest if you are correct
Answer:
A. non renewable energy sources cannot be used over again and renewable energy sources can be used again
Answer:
A. Nonrenewable energy sources cannot be used over again. Renewable energy sources can be used again.
Explanation:
I need help with level 15 in covalent bonding in playmada collisions app.
which level are u on now?
Research and describe one career in health and fitness that you would consider
Answer:
a PE teacher would be in both catagories of heath and fitness
Explanation:
Why does an orange look orange?
Ο Α.
It reflects orange light and absorbs other colors.
O B. It absorbs orange light and reflects other colors.
C.
It reflects red and yellow light, only.
O D.
D. It absorbs red and yellow light, only.
What products will form when potassium is added to cold, liquid water?
A.) no reaction will occur
B.) potassium oxohydride and hydrogen
C.) potassium hydroxide and hydrogen
4.) potassium oxide and hydrogen
Answer:
C
Explanation:
Potassium metal reacts very rapidly with water, which forms Potassium hydroxide (KOH) and hydrogen gas (H2).
Answer:
The answer is C
Explanation:
i took a test on this.
How do you balance: Al+Fe3O4=Al2O3+Fe ?
Answer:
8Al+3Fe3O4=4Al2O3+9Fe
Answer:
8Al + 3Fe3O4 → 4Al2O3 + 9Fe
Explanation:
You prepare a standard by weighing 10.751 mg of compound X into a 100 mL volumetric flask and making to volume. You further dilute this solution 5 mL to 25 mL. This standard gives an area of 4,374. Your sample is prepared by adding 5 mL of sample solution into a 50 mL flask and making to volume. This gives an area count of 2,582. Calculate the concentration of compound X in the sample - prior to dilution.
Answer:
0.12693 mg/L
Explanation:
First we calculate the concentration of compound X in the standard prior to dilution:
10.751 mg / 100 mL = 0.10751 mg/mLThen we calculate the concentration of compound X in the standard after dilution:
0.10751 mg/mL * 5 mL / 25 mL = 0.021502 mg/LNow we calculate the concentration of compound X in the sample, using the known concentration of standard and the given areas:
2582 * 0.021502 mg/L ÷ 4374 = 0.012693 mg/LFinally we calculate the concentration of X in the sample prior to dilution:
0.012693 mg/L * 50 mL / 5 mL = 0.12693 mg/LOptions:
1. Unsaturated fat or saturated fat
2. Fatty acids, carbohydrates, sterols, or phospholipids
3. Fatty acids, carbohydrates, or triglycerides
Answer:
saturated fats
Explanation:
bcoz it is solid at room temperature and does not have double bonds between carbons
1. What organ system is responsible for controlling all of the body
functions?
Answer:
The human brain is the body's control center, receiving and sending signals to other organs through the nervous system and through secreted hormones. It is responsible for our thoughts, feelings, memory storage and general perception of the world. The human heart is a responsible for pumping blood throughout our body
.35L sample of helium gas is collected at 295 K and 0.98 ATM what volume would this gas occupy at STP
Answer:
0.3857 litres is the answer
What mass of nitrogen (N2) is needed to produce 0.125 mol of ammonia (NH3)? Input a numerical answer only. N2 + 3H2 ---> 2NH:
Please help me
How much heat is transferred when 7.19 grams of H2 reacts with excess nitrogen, according to the following equation: N2(g) + 3 H2 (g) --> 2 NH3 (g) \DeltaΔH = +46.2 kJ
Answer:
[tex]Q=54.8kJ[/tex]
Explanation:
Hello there!
In this case, according to the given chemical reaction, it is possible for us to realize that the 46.2 kJ of energy are given per mole of reaction, which are related to 3 moles of hydrogen; Thus, we can calculate the energy per mole of hydrogen as shown below:
[tex]\Delta H=\frac{46.2kJ}{mol} *\frac{1mol}{3molH_2}\\\\ \Delta H=15.4\frac{kJ}{molH_2}[/tex]
Now, to calculate the total energy, we convert the grams to moles of hydrogen as shown below:
[tex]Q=7.19gH_2*\frac{1molH_2}{2.02gmolH_2}*15.4\frac{kJ}{molH_2} \\\\Q=54.8kJ[/tex]
Best regards!
Explain how a neutral paper fragment can be attracted to a charged rod
Answer:
The particles in the neutral paper can shift, causing the paper to become polarized and attracted to the rod.
Explanation:
The neutral paper has an even distribution of its electrons throughout the paper. If a charged rod is brought near the neutral paper, this can cause the electrons in the paper to shift. If the rod is negative, the electrons will be repelled from the rod and cause the molecules in the paper to have a slight positive charge on the part of the paper closest to the rod. If the rod is positive, the electrons will be attracted to the rod and cause a slight negative charge on the side of the paper closest to the rod.
Arrange the following substance into acid,base and neutral. sodium chloride, tomato juice, vinegar,sea water,bicorbonate of sodium
Answer:
sodium chloride: neutral.
tomato juice: acid.
vinegar: acid.
sea water: base.
bicarbonate of sodium: base.
Explanation:
Hello there!
In this case, in agreement to the definition of the pH, as the measure of the acidity and basicity of a substance; it is important to recall that pH's below 7 stand for acidic substances and pH's above 7 stand for basic substances, whereas a pH of 7 defines a neutral one. In such a way, given the pH's of the given substances, 7, 4.05 to 4.65, around 2.5, about 8.1 and about 8.3 respectively for sodium chloride, tomato juice, vinegar, sea water, bicarbonate of sodium, it is possible to assert:
sodium chloride: neutral.
tomato juice: acid.
vinegar: acid.
sea water: base.
bicarbonate of sodium: base.
Best regards!
How many milliliters of 0.100 M NaOH is needed to titrate 20.0 mL of 0.100 M HNO3 ?
How much of the excess reagant in Problem 1 is left over?
Answer:
4 Al + 3 O2 → 2 Al2O3
(10.0 g Al) / (26.98154 g Al/mol) = 0.37062 mol Al
(19.0 g O2) / (31.99886 g O2/mol) = 0.59377 mol O2
0.37062 mole of Al would react completely with 0.37062 x (3/4) = 0.277965 mole of O2, but there is more O2 present than that, so O2 is in excess.
((0.59377 mol O2 initially) - (0.277965 mol O2 reacted)) x (31.99886 g O2/mol) =
10.1 g O2 left over
Explanation:
i really hope this is what you were looking for <3 :)
what is bond stability??
Answer:
Bond order is a counting method that gives an idea about numbers of electrons shared between atoms. A species with a higher bond order is more stable. A bond order equal to 2 is a double bond, and a bond order of 3 is a triple bond.
Explanation:
A scientist wants to display the numbers of gallons of fuel that were used up
in a one-hour period by three different types of motors. What type of visual
display should the scientist use?
Help please
Answer:
bar graph
Explanation:
Help me I'm desperate :( no links or u will be reported
Answer:
Here is the answer from somewhere in the internet
Which of the following is an exothermic reaction?
a solid to a liquid
a gas change to a liquid
a liquid to a gas
a solid to a gas
Answer:
liquid to gas
Explanation:
when boiling water when evaporating heat is given out
Can you watch the video and help me fill in the blanks ? Thank you
True/False –Similar to liquids, gases cannot be compressed.
Answer:
False
Explanation:
A liquid has a definite shape and takes on the volume of its container. A gas has both the shape and the volume of its container. The particles in a gas cannot be compressed into a smaller volume. Liquids tend to contract when heated.
Hope this helps
What are the benefits of Fluoride?
Answer:
The benefits of Fluoride are rebuild (remineralize) weakened tooth enamel.slow down the loss of minerals from tooth enamel.reverse early signs of tooth decay.prevent the growth of harmful oral bacteria
Answer:
Fluoride is often called nature's cavity fighter and for good reason. Fluoride, a naturally-occurring mineral, helps prevent cavities in children and adults by making the outer surface of your teeth (enamel) more resistant to the acid attacks that cause tooth decay.
The solubility of a solid in a liquid generally increases with increase temperature.
True
Or
False
Answer:
False, Solubility increases with temperature for most solids.
Explanation:
Pleaseeeee helpppp!!!
Answer:
a triple bond posana pi maka tulong
The process of breaking a compound down into its elements is called
rearrangement
recombination
decomposition
dessication
2. What organelle in plant cells makes it possible for plants to carry out photosynthesis?
a. cell wall
b. chloroplast
C. lysosome
d. nucleus
Select the valid ways to make an ammonia/ammonium buffer for use in the laboratory. Mix equal volumes of 1 M NH3 and 0.01 M NH 4. Mix some volume of 1 M NH3 with half as much 1 M HCl. Mix equal volumes of 1 M NH3 and 1 M NH 4. Mix equal volumes of 1 M NH3 and 1 M HCl.
Answer:
The answer is "Option b and Option c".
Explanation:
This buffer is a buffer of ammonia and ammonium ion. Thus it requires the solution [tex]NH_3 \ \ and \ \ NH_4^{+}[/tex].
In point 1:
The solution containing [tex]NH_3 \ \ and \ \ NH_4^{+}[/tex] at 1M concentration would be given by mixing the two solutions. Thus, this buffer is a legitimate route.
In point 2:
It gives the ions you want but they are not the same.
In point 3:
[tex]1 M[/tex] [tex]NH_3[/tex] and [tex]1 M[/tex][tex]HCl[/tex] volume would not produce the same [tex]NH_3 \ \ and \ \ NH_4^{+}[/tex] concentrations. Therefore, this buffer isn't a valid route.
In point 4:
Some [tex]1 M[/tex] [tex]NH_3[/tex] volume and half [tex]HCl[/tex] . This offers the same rate as half.
PART A: Which of the following statements best identifies a central idea of the article?
A. The media attention on Mars enthusiasts has caused space exploration to become one of the
most important issues facing Americans today.
B. While some private agencies are working on sending humans to Mars, many experts believe
that the barriers to such a voyage still remain high.
C. Despite the publicity surrounding private space missions, NASA remains optimistic that it
will be the first agency in the U.S. to send humans to Mars.
D. Private space agencies have no plans beyond landing on Mars, as opposed to the people of
NASA, who genuinely want to colonize Mars and explore space.
The central idea is despite publicity surrounding private space missions, NASA remains optimistic that it will be the first agency to send humans to Mars.
What is NASA?This is referred to as National Aeronautics and Space Administration and are involved in the science and technology related to space.
The article talks about publicity of private space missions and NASA being optimistic about being the first to achieve the feat of sending humans to Mars.
Read more about NASA here https://brainly.com/question/1350178
Write a net ionic equation for the reaction that occurs when aqueous solutions of hydrofluoric acid and barium hydroxide are combined. Include solubility states
Answer: The net ionic equation is [tex]2H^+(aq)+2F^-(aq)+Ba^{2+}(aq)+2OH^-(aq)\rightarrow BaF_2(s)+2H_2O(l)[/tex]
Explanation:
The net ionic equation of any reaction does not include any spectator ions.
Spectator ions are defined as ions that do not get involved in a chemical equation. They are found on both the sides of the chemical reaction when it is present in ionic form.
The chemical equation for the reaction of hydrofluoric acid and barium hydroxide follows:
[tex]2HF(aq)+Ba(OH)_2(aq)\rightarrow BaF_2(s)+2H_2O(l)[/tex]
The ionic form of the above equation follows:
[tex]2H^+(aq)+2F^-(aq)+Ba^{2+}(aq)+2OH^-(aq)\rightarrow BaF_2(s)+2H_2O(l)[/tex]
There are no spectator ions in the ionic form.
The net ionic equation for the above reaction follows:
[tex]2H^+(aq)+2F^-(aq)+Ba^{2+}(aq)+2OH^-(aq)\rightarrow BaF_2(s)+2H_2O(l)[/tex]