Answer:
We can see the bright matter, like stars, but we know some other matter is there(dark matter)because of how it pulls on the bright matter.
Explanation:
Answer : Option B) All atoms of a single substance are identical.
Explanation : The scientist John Dalton proposed the atomic theory which had the postulates as follows.
i) All matter/substances consists of indivisible particles known as atoms.
ii) Atoms of the same element/substance are similar in mass,shape and size, but differ from the atoms of other elements.
iii) Atoms obey the law of conservation of energy which says atoms cannot be created or destroyed.
iv) Atoms of different elements may combine with each other in a fixed, simple, whole number ratios to form any compound atoms.
v) Atoms of same element can combine in ratio with more than one to form two or more compounds.
vi) The atom is considered to be the smallest unit of matter that can take part in a chemical reaction
The balanced equation :
2KOH+CO₂⇒K₂CO₃+H₂O
<h3>Further explanation</h3>
Equalization of chemical reaction equations can be done using variables. Steps in equalizing the reaction equation:
1. gives a coefficient on substances involved in the equation of reaction such as a, b, or c etc.
2. make an equation based on the similarity of the number of atoms where the number of atoms = coefficient × index between reactant and product
3. Select the coefficient of the substance with the most complex chemical formula equal to 1
Reaction
KOH+CO₂⇒K₂CO₃+H₂O
aKOH+bCO₂⇒K₂CO₃+cH₂O
K, left=a, right=2⇒a=2
H, left=a, right=2c⇒a=2c⇒2=2c⇒c=1
O, left=a+2b, right=3+c⇒a+2b=3+c⇒2+2b=3+1⇒2b=2⇒b=1
the equation becomes :
2KOH+CO₂⇒K₂CO₃+H₂O
The correct answer is C. Liquid
A compound is a pure substance formed by the chemical combination of two or more different elements.
A compound may be splitted into simpler substances by chemical reactions, and has different properties to those of the elements that form it.
The composition of a compound is fixed: every piece of a compound has the same kind of atoms, bonded in the same way and proportion.
Some examples of compounds are H₂O, NaCl, H₂O₂, CH₃COOH. As you see, they have a chemical formula which states the kind and number of the atoms that form them.
They are different to mixtures, which are formed by two or more compounds, in a variable proportion, and can be separated by physical media. Some examples of mixtures are the solutions (e.g. NaCl dissolved in H₂O), and some solid mixtures (e.g. a mixture of marbles and sand).
