1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Travka [436]
2 years ago
7

can someone help me with these? I just started chemistry this semester, and since it's involving math I don't see myself doing g

ood.

Chemistry
1 answer:
V125BC [204]2 years ago
4 0

Any non zero digits are significant. (120 has 2 sig figs)

Zeroes between significant digits are significant. (103 has 3 sig figs)

Zeroes only count if there is a decimal point and if they are following a significant digit. (.600 has 3 sig figs; .067 has 2 sig figs)

1) <u>1278.50</u> = 6 sig figs

2) <u>12</u>0000 = 2 sig figs

3) <u>90027.00</u> = 7 sig figs

4) 0.00<u>53567</u> = 5 sig figs

5) <u>67</u>0 = 2 sig figs

6) 0.00<u>730</u> = 3 sig figs

That's all I'm gonna do so yeah.

Now for the rounding, it's basically rounding but it must have the x amount of sig figs after rounding. It's pretty hard to explain.

19, I'm not really sure. Might be 120 with a decimal point at the end.

20) 5.457, alright so here, since we are rounding to three significant digits, we look at the third sig fig. The third sig fig here would be 5. Then we just round. Since the number next to 5 is 7, we round 5 up to 6.

So 5.457 rounded to 3 sig figs would be 5.46

21) 0.0008769, the third sig fig here would be 6. You round 6 up to 7 because the number next to it is 9.

So 0.0008769 rounded to 3 sig figs would be 0.000877

So I hope you get it, I'm gonna let you do the rest.

You might be interested in
Explain why a total lunar eclipse appears red.<br> I
DochEvi [55]

Answer:

During a total lunar eclipse, the Earth lies directly between the sun and the moon, causing the Earth to cast its shadow on the moon.

Explanation:

4 0
3 years ago
When can all the coefficients in a balanced equation represent volume ratios? when reactants and products are solids at stp when
Alexxx [7]

Answer: when reactants and products are gases at STP.


Justification:


1) STP stands for standard temperature (0°) and pressure (1 atm).


2) According to the kinetic molecular theory of the gases, and as per Avogadro's principle, equal volumes of gases, at the same temperature and pressure, have the same number of molecules.



3) Since the coefficients in a balanced chemical equation represent number of moles, when reactants and products are gases at the same temperature and pressure, the mole ratios are the same that the volume ratios, and then the coefficients of the chemical equation represent the volume ratios.


8 0
3 years ago
Read 2 more answers
A 155.0 g piece of copper at 128 oC is dropped into 250.0 g of water at 17.9 oC. (The specific heat of copper is 0.385 J/goC.) C
Mamont248 [21]

Answer:

T_{eq}=23.85^oC

Explanation:

Hello,

In this case, as the copper's heat loss is gained by the water, the following energetic relationship is:

\Delta H_{Cu}=-\Delta H_{H_2O}

Therefore the equilibrium temperature shows up as:

m_{Cu}Cp_{Cu}(T_{Cu}-T{eq}) = m_{H_2O}Cp_{H_2O}(T_{eq}-T_{H_2O})\\\\T_{eq}=\frac{m_{Cu}Cp_{Cu}T_{Cu}-m_{H_2O}Cp_{H_2O}T_{H_2O}}{m_{Cu}Cp_{Cu}-m_{H_2O}Cp_{H_2O}} \\

Thus, by knowing that water's heat capacity is 4.18J/g°C, one obtains:

T_{eq}=\frac{155.0g*0.385\frac{J}{g^oC}*128^oC+250.0g*4.18\frac{J}{g^oC}*17.9^oC}{155.0g*0.385\frac{J}{g^oC}+250.0g*4.18\frac{J}{g^oC}}=23.85^oC

Best regards.

6 0
3 years ago
Read 2 more answers
Which describes a stationary reference point?
kondaur [170]

Answer: C

Explanation:

7 0
3 years ago
Substance X has a fixed volume, and the attraction between its particles is strong. Substance Y has widely spread out particles
ycow [4]

Answer: Option (d) is the correct answer.

Explanation:

In solids, molecules are held together by strong intermolecular forces of attraction. As a result, they are unable to move from their initial position and can only vibrate at their mean position.

Hence, a solid has definite shape and volume. Solids cannot be compressed.

Whereas in plasma, molecules are hot ionized which include positively charged ions and negatively charged electrons. They collide much more rapidly with each other and are widely spreaded out.

Therefore, they occupy the volume of container in which they are placed. Plasma can be compressed.

Thus, we can conclude that substance X is a solid and substance Y is a plasma.

6 0
2 years ago
Read 2 more answers
Other questions:
  • A car moves at a speed of 50 kilometers/hour. Its kinetic energy is 400 joules. If the same car moves at a speed of 100 kilomete
    11·2 answers
  • If 200 mg of HCl is added to water to achieve a final volume of 1L, what is the final pH?
    9·2 answers
  • What do all organic substances have in common
    10·1 answer
  • 1. What is the frequency of light having a wavelength of 406 nm?
    9·1 answer
  • Classify each of the following changes as Physical or Chemical:
    6·1 answer
  • Which is the electron configuration for zinc?
    6·2 answers
  • Write the proper word equation to express the following chemical reaction: 4Fe (s) + 3Sn(NO3)4 (aq) arrow 4Fe(NO3)3 (aq) + 3Sn (
    7·1 answer
  • For the reaction, calculate how many grams of the product form when 1.8 g of cao completely reacts. assume that there is more th
    7·1 answer
  • Can someone plz help me in this thanks for number 1. Only
    13·1 answer
  • 3.How are climate and weather different?
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!