Answer:
D. lt is exothermic is the correct ans
In a solution containing 21.2 g sodium carbonate in 1.50 L of solution, calculate
the concentration of the sodium and carbonate ions.
Answer:
0.13 molL-1
Explanation:
We must first obtain the number of moles of sodium carbonate as follows;
Number of moles = mass/molar mass
Number of moles = 21.2 g/106 g/mol
Number of moles= 0.2 moles
Number of moles = concentration × volume
Volume = 1.50 L
Concentration = number of moles/volume
Concentration = 0.2 moles/1.5 L
Concentration = 0.13 molL-1
Which of the following is not a part of every scientific investigation?
Group of answer choices
Collection of relevant empirical evidence
Using models to understand objects and processes better
Use of logical reasoning
Devising hypothesis, making predictions
Answer:
the correct answer is Group of answer choices
Using models to understand objects and processes better is not part of every scientific investigation while collection of relevant empirical evidence,use of logical reasoning and devising hypothesis, making predictions is a part.
What is hypothesis?Hypothesis can be defined as an assumption which is made for the sake of argument . It is an interpretation of a practical condition for which action needs to be taken.It is defined as a tentative assumption which is made to test logical consequences.It is an antecedent clause of a statement which is conditional.
It is constructed before research. There are six types of hypothesis 1)simple hypothesis 2) complex hypothesis 3) directional hypothesis 4)non-directional hypothesis 5) null hypothesis 6)casual hypothesis
The hypothesis should be clear and precise, it must be specific and way of explanation of hypothesis should be simple.
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If 9.9L of helium are in a tire at 303k,how many liters will be present at 403k if the pressure is held constant.
Answer:
Final volume, V2 = 13.18 Liters
Explanation:
Given the following data;
Initial volume = 9.9 L
Initial temperature = 303 K
Final temperature = 403 K
To find the final volume, we would use Charles law;
Charles states that when the pressure of an ideal gas is kept constant, the volume of the gas is directly proportional to the absolute temperature of the gas.
Mathematically, Charles' law is given by the formula;
[tex] VT = K[/tex]
[tex] \frac{V_{1}}{T_{1}} = \frac{V_{2}}{T_{2}}[/tex]
Where;
V1 and V2 represents the initial and final volumes respectively.T1 and T2 represents the initial and final temperatures respectively.[tex] \frac{V1}{T1} = \frac{V2}{T2}[/tex]
Making V2 as the subject formula, we have;
[tex] V_{2}= \frac{V1}{T1} * T_{2}[/tex]
[tex] V_{2}= \frac{9.9}{303} * 403 [/tex]
[tex] V_{2}= 0.0327 * 403 [/tex]
Final volume, V2 = 13.18 Liters
If I have 0.294L of a 2.OM NaOH solution, what will be the concentration if I add 1.824L to the solution?
Answer:
0.32M
Explanation:
Using the following formula;
CaVa = CbVb
Where;
Ca = concentration of acid (M)
Cb = concentration of bass (M)
Va = volume of acid (HCl)
Vb = volume of base (NaOH)
According to this question, the following were given:
Ca = ?
Cb = 2M
Va = 1.824L
Vb = 0.294L
Using CaVa = CbVb
Ca × 1.824 = 0.294 × 2
1.824Ca = 0.588
Ca = 0.588 ÷ 1.824
Ca = 0.32M
How many moles are in 3.45 g of Na2O?Round your answer to three significant
figures. IN A FINAL EXAM HURRY PLEASE
Answer: There are 0.056 moles present in 3.45 g of [tex]Na_{2}O[/tex].
Explanation:
Given : Mass = 3.45 g
Moles is the mass of substance divided by its molar mass.
Hence, moles of [tex]Na_{2}O[/tex] (molar mass = 61.98 g/mol) is as follows.
[tex]Moles = \frac{mass}{molar mass}\\= \frac{3.45 g}{61.98 g/mol}\\= 0.056 mol[/tex]
Thus, we can conclude that there are 0.056 moles present in 3.45 g of [tex]Na_{2}O[/tex].
A hot metal plate at 150°C has been placed in air at room temperature. Which event would most likely take place over the next few minutes? Molecules in both the metal and the surrounding air will start moving at lower speeds. Molecules in both the metal and the surrounding air will start moving at higher speeds. The air molecules that are surrounding the metal will slow down, and the molecules in the metal will speed up. The air molecules that are surrounding the metal will speed up, and the molecules in the metal will slow down.
Answer:
last option is correct.
Air molecules surrounding the metal will speed up and metal molecules will slow down
Explanation:
the metal cools when placed in room temperature air which causes surrounding air to heat up.
the speed of molecules slow down for any material which cools and molecules speed increases when any material heats up
The atoms of elements A (blue) and B (orange) form 2 compounds shown here. Do these compounds obey the law of multiple proportions?
Hello. You have not presented the image that presents the two elements mentioned in the question. This makes it impossible for your question to be answered. However, I will try to help you as best I can.
To say whether the compounds obey the law of multiple proportions, you should observe whether one of the elements, formed from the compounds, maintains a fixed mass, while the other element presents the mass in a varied amount of small, whole numbers, spread across the formed compounds .
This is because the law of multiple proportions states that an element must have a fixed mass when reacting with another element to create compounds. This reaction will allow this element to keep the mass fixed, while the other element will generate different compounds, where each one presents a part of the mass of the forming element, in small and whole numbers.
Will these magnets attract or repel?
Attract
Repel
Answer:
repel, if you stick them together as they are, because the north and south poles are next to each other
Explanation:
A block is pulled 0.90 m to the right in 2.4 s. What is the block's average speed to the nearest hundredths of a m/s?
whats the net ionic and total ionic equations? include the ions and states pls:
NiCl2 + Na2CO3 = 2NaCl + NiCO3
Answer:
Total ionic equation = Ni²⁺ + 2Cl⁻¹ + 2Na⁺ + CO₃⁻² → 2Na⁺ + 2Cl⁻¹ + NiCO₃ (s)
Net ionic equation = Ni²⁺ + CO₃⁻² → NiCO₃ (s)
NiCl₂ (aq) + Na₂CO₃ (aq) → 2NaCl (aq) + NiCO₃ (s)
First, we'll need to expand the complete chemical equation into a total ionic equation (to determine whether a chemical is aqueous or solid, use a solubility chart until the rules are memorized).
Ni²⁺ + 2Cl⁻¹ + 2Na⁺ + CO₃⁻² → 2Na⁺ + 2Cl⁻¹ + NiCO₃ (s)
Now, using the total ionic equation, we can find the net ionic equation. In order to do this, we need to cancel out the aqueous solutions that don't form into solids, as they are extraneous.
Ni²⁺ + 2Cl⁻¹ + 2Na⁺ + CO₃⁻² → 2Na⁺ + 2Cl⁻¹ + NiCO₃ (s)
Ni²⁺ + CO₃⁻² → NiCO₃ (s)
I hope this helped!
Which of the following combinations of compounds will make a buffer when
mixed?
A. HCl and NaOH
B. CH3COOH and NaCH3Coo
C.HCl and NaBr
D. CH3COOH and NHACI
Answer:
B. CH3COOH and NaCH3COO
Explanation:
CH3COOH and NaCH3COO will make a buffer when mixed.
What is a buffer solution?Buffer solutions resist a change in pH when small amounts of a strong acid or a strong base are added. A solution of acetic acid and sodium acetate CH3COOH + CH3COONa is an example of a buffer that consists of a weak acid and its salt.
What are buffer solutions and their types?Buffers are broadly divided into two types – acidic and alkaline buffer solutions. Acidic buffers are solutions that have a pH below 7 and contain a weak acid and one of its salts. For example, a mixture of acetic acid and sodium acetate acts as a buffer solution with a pH of about 4.75.
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Which gas is produced when a carbonate undergoes thermal decomposition
Answer:
carbon dioxide gas
Explanation: This type of reaction is called a thermal decomposition. This reaction is very common in where carbon dioxide gas makes Products rise..
Please help .. I’m really stuck
Answer:
See explanation
Explanation:
pOH = -log[OH^-]
pOH =-log[1×10^-4 molL-1]
pOH = 4
pH +pOH =14
pH = 14 -4
pH =11
b) pOH = -log[OH^-]
pOH =-log[4.9×10^-2molL-1]
pOH = 1.31
pH +pOH =14
pH = 14 -1.31
pH =12.69
c)
pH= -log[H^+]
[H^+] = Antilog [-pH]
[H^+] = Antilog [-3]
[H^+] = 1 × 10^-3 molL-1
d) pOH = -log[OH^-]
[OH^-] = Antilog[-pOH]
[OH^-] = Antilog[-10.4]
[OH^-] = 3.98 ×10^-11
[OH^-] [H^+] = 1 × 10^-14
[H^+] = 1 × 10^-14/3.98 ×10^-11
[H^+] =2.5 ×10^-4 MolL^-1
e) A solution of pH 9 is basic because the pH scale is calibrated in such as way that 0-6.9 is acidic, 7 is neutral and 8 - 14 is basic.
f)
[H^+] = number of moles/volume
[H^+] = 0.35 moles/8L
[H^+] = 0.044 MolL^-1
pH = - log [H^+]
pH = -log [0.044 MolL^-1]
pH= 1.36
Which is the correct Lewis dot structure of NH2-?
Answer:
A
Explanation:
because it can share and remain with ither electrons
Most terrestrial plants are members of this Division:
Bryophyta
Angiosperms
Pinophyta
Pteridophyta
Answer:
most flowering plants are classified as angiosperms
Answer:
I think the answer is Bryophyta
Explanation:
seedless,non vascular plants that are the closest extant relative of early terrestrial plants
Which diagram shows a pair of electrons that have opposite spins?
O1
1
个个
Answer:
the answer is half arrow
Please somone help me with a chemistry question brainliest to whoever answers correctly and 20 points
Answer:
258.15 enjoy
Explanation:
2. Measure the length of a page in centimeters to the nearest tenth of a centimeter with the metric edge of a ruler. Note that nine lines divide the space between each centimeter into 10 millimeters.
The page is ____27.5____ cm long
58
Explanation:
ccause that is how long it is
1. What is the volume of 4.00g of aluminum at STP?
Answer:
22.4cm³
Explanation:
Avogadro's law shows that Avogadro's volume is 22.4
How do protons and neutrons stay together in a nucleus?
A Electrostatic forces hold them together
B. Gravitational forces hold them together
C Weak nuclear forces hold them together
D. Strong nuclear forces hold them together
Answer:
strong nuclear forces that hold them together
any of ya'll good at chemistry?????
Answer:
i good at chemistry
Explanation:
not all but i try
According to the Law of Conservation of Mass, the total
moles of reactants in a balanced chemical equation is...?
O always equal to the total moles of the products.
sometimes more or sometimes less than the total moles of the products.
O always more than the total moles of the products.
O always less than the total moles of the products.
Answer:
Always equal to the total moles of the products.
Explanation:
The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction equal to the mass of the reactants.
Give me formula for
1)Aluminium chloride
2) Copper sulphate
3) Zinc Nitrate
3) Ammonium Carbonate
Answer:
1. AlCl₃
2. CuSO4
3. Zn(NO₃)₂
4. (NH4)2CO3
what is a metal ore?
Answer:
metal ores are naturally occurring rocks that contain metals or metal compounds in sufficient amounts to make it worthwhile extracting them
Which properties make a metal a good material to use for electrical wires?
Answer: it has 2 characteristics and they are conductivity and ductility
Explanation:
The conductivity makes them great conductors of electricity
Answer:
It's B guaranteed;)
Conductivity and ductility
why is baking powder a substance
Answer:
Baking powder is a dry chemical leavening agent, a mixture of a carbonate or bicarbonate and a weak acid. Because carbon dioxide is released at a faster rate through the acid-base reaction than through fermentation.
Baking powder is a mixture because it contains both sodium hydrogen phosphate and potassium hydrogen tartrate (two different compounds.)
Under what conditions is AG for a reaction always positive?
What value is closest to the mass of the atom ?
Answer:
mass number
Explanation:
Answer and Explanation: The value closest to the mass of an atom is its mass number. The mass number is the total count of the protons and neutrons in the nucleus of the...
mass number
hope that helped
Can someone please help me!!
Explanation:
Corrections
- It should be 45 bromine atoms
- Bromine isn't found abundantly as atoms, rather as diatomic molecules
[tex]Br_2[/tex]
Before should show 2 phosphorus atom and 3 bromine molecules to form 2 phosphorus tribromide
The bond is covalent because both bromine and phosphorus is a non-metal
The volume of a gas at 5.00 ATM is 3.5 L what is the volume of the gas at 7.00 ATM at the same temperature
A- 2.5 L
B- 5.0 L
C- 10. L
D- 12 L
Answer:
B) 5.0L
Explanation:
Like the Ford F-150 V8 Cyote 5.0L engine